Resin composition, prepreg, resin-added film, resin-added metal foil, metal-clad layered plate, and wiring plate

ABSTRACT

A resin composition is provided and contains a compound (A) having at least one group represented by the following Formula (1) in a molecule, a crosslinking type curing agent (B), and an azo compound (C) that has an azo group in a molecule and has no heteroatom other than a nitrogen atom constituting the azo group.In Formula (1), n represents 0 to 10, Z represents an arylene group, and R1 to R3 each independently represent a hydrogen atom or an alkyl group.

TECHNICAL FIELD

The present invention relates to a resin composition, a prepreg, a filmwith resin, a metal foil with resin, a metal-clad laminate, and a wiringboard.

BACKGROUND ART

As the information processing quantity by various kinds of electronicequipment increases, mounting technologies such as high integration ofsemiconductor devices to be mounted, densification of wiring, andmulti-layering are progressing. In addition, wiring boards to be used invarious kinds of electronic equipment are required to be, for example,high-frequency compatible wiring boards such as a millimeter-wave radarboard for in-vehicle use. Wiring boards to be used in various kinds ofelectronic equipment are required to decrease the loss during signaltransmission in order to increase the signal transmission speed, andthis is especially required for high-frequency wiring boards. In orderto meet this requirement, substrate materials for forming substrates ofwiring boards to be used in various kinds of electronic equipment arerequired to have a low dielectric constant and a low dielectric losstangent. Examples of such substrate materials include a resincomposition containing polyphenylene ether.

Meanwhile, molding materials such as substrate materials are required toexhibit not only excellent low dielectric properties but also excellentheat resistance and the like. From this fact, it is considered that theresin contained in the substrate material is modified so as to bepolymerized together with a curing agent and the like and, for example,a vinyl group and the like are introduced thereinto to improve the heatresistance.

Examples of such substrate materials include the resin compositiondescribed in Patent Literature 1. Patent Literature 1 describes apolyphenylene ether compound which contains polyphenylene ether and acrosslinking type curing agent, has a polyphenylene ether moiety in themolecular structure, an ethenylbenzyl group and the like at thismolecule terminal, and a number average molecular weight of 1,000 to7,000.

Patent Literature 1 discloses that a laminate which has a low dielectricconstant and a low dielectric loss tangent and exhibits high heatresistance, moldability and the like can be obtained. It is consideredthat a wiring board obtained by using a resin composition exhibiting lowdielectric properties such as dielectric constant and dielectric losstangent as described in Patent Literature 1 can decrease the loss duringsignal transmission. On the other hand, it is required that the signaltransmission speed on the wiring board is further increased and the heatresistance is higher from the viewpoint of product stability and thelike. Hence, the material used as a substrate material is required toexhibit lower dielectric properties and higher heat resistance.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2006-516297 A

SUMMARY OF INVENTION

The present invention has been made in view of such circumstances, andan object thereof is to provide a resin composition which provides acured product exhibiting low dielectric properties and high heatresistance. Another object of the present invention is to provide aprepreg, a film with resin, a metal foil with resin, a metal-cladlaminate, and a wiring board which are obtained using the resincomposition.

An aspect of the present invention is a resin composition containing acompound (A) having at least one group represented by the followingFormula (1) in a molecule, a crosslinking type curing agent (B), and anazo compound (C) that has an azo group in a molecule and has noheteroatom other than a nitrogen atom constituting the azo group.

In Formula (1), n represents 0 to 10, Z represents an arylene group, andR₁ to R₃ each independently represent a hydrogen atom or an alkyl group.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following detailed description.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic sectional view illustrating an example of aprepreg according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view illustrating an example of ametal-clad laminate according to an embodiment of the present invention.

FIG. 3 is a schematic sectional view illustrating an example of a wiringboard according to an embodiment of the present invention.

FIG. 4 is a schematic sectional view illustrating an example of a metalfoil with resin according to an embodiment of the present invention.

FIG. 5 is a schematic sectional view illustrating an example of a filmwith resin according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The present inventors have carried out various investigations in orderto provide a resin composition which is superior in heat resistance andlow dielectric properties to the conventional resin compositions, forexample, the resin composition described in Patent Literature 1. At thattime, attention has been paid to the fact that the resin compositiondescribed in Patent Literature 1 has a high dielectric constant and ahigh dielectric loss tangent in some cases. Moreover, the presentinventors have carried out investigations based on an inference that thedielectric properties such as dielectric constant and dielectric losstangent are also affected by the kind of initiator and, as a result,found out that the dielectric constant and dielectric loss tangent tendto increase when the initiator described in Patent Literature 1 is used.Specifically, the dielectric constant and dielectric loss tangent tendto increase when an azo compound containing a hetero atom in addition toan azo group and a peroxide are used as an initiator. As the reason forthis, it has first been inferred that the dielectric constant anddielectric loss tangent increase when an azo compound containing ahetero atom in addition to an azo group since a highly polar group suchas a CN group is generated in the cured product of the resincomposition. It has also been inferred that the dielectric constant anddielectric loss tangent increase even when a peroxide is used as aninitiator since highly polar groups such as an ether group and ahydroxyl group are generated in the cured product of the resincomposition. Hence, the present inventors have achieved the followinginvention by using an initiator other than an azo compound containing ahetero atom in addition to an azo group and a peroxide, namely, an azocompound which has an azo group in the molecule and has no heteroatomother than a nitrogen atom constituting the azo group as an initiator.

Hereinafter, embodiments according to the present invention will bedescribed, but the present invention is not limited thereto.

[Resin Composition]

The resin composition according to the embodiments of the presentinvention is a resin composition containing a compound (A) having atleast one group represented by the following Formula (1) in themolecule, a crosslinking type curing agent (B), and an azo compound (C)that has an azo group in the molecule and has no heteroatom other than anitrogen atom constituting the azo group.

In Formula (1), n represents 0 to 10. Z represents an arylene group. R₁to R₃ are independent of each other. In other words, R₁ to R₃ may be thesame group as or different groups from each other. R₁ to R₃ represent ahydrogen atom or an alkyl group.

The arylene group in Formula (1) is not particularly limited. Examplesof this arylene group include a monocyclic aromatic group such as aphenylene group, and a polycyclic aromatic group in which the aromaticis not a single ring but a polycyclic aromatic such as a naphthalenering. This arylene group also includes a derivative in which a hydrogenatom bonded to an aromatic ring is substituted with a functional groupsuch as an alkenyl group, an alkynyl group, a formyl group, analkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonylgroup.

The alkyl group represented by R₁ to R₃ in Formula (1) is notparticularly limited, and for example, an alkyl group having 1 to 18carbon atoms is preferable and an alkyl group having 1 to 10 carbonatoms is more preferable. Specific examples thereof include a methylgroup, an ethyl group, a propyl group, a hexyl group, and a decyl group.

It is considered that the resin composition provides a cured productexhibiting high heat resistance as the compound (A) and the crosslinkingtype curing agent (B) are reacted to be crosslinked with each other. Itis considered that the azo compound (C) contained in the resincomposition acts as an initiator at the time of this reaction. Asdescribed above, this azo compound (C) contains a nitrogen atom that isa hetero atom in the azo group contained in the molecule and has noheteroatom other than the nitrogen atom constituting the azo group. Itis considered that a highly polar group such as a CN group is hardlygenerated in the cured product of the resin composition and a curedproduct having a low dielectric constant and a low dielectric losstangent is obtained when the compound (A) and the crosslinking typecuring agent (B) are reacted using such an azo compound (C) as aninitiator.

From the above fact, a resin composition having the configuration is aresin composition which provides a cured product exhibiting lowdielectric properties and high heat resistance.

(Compound (A))

The compound (A) is not particularly limited as long as it is a compoundhaving at least one group represented by Formula (1) in the molecule. InFormula (1), when n is 0, it indicates that Z that is an arylene groupis directly bonded to the terminal or the molecular chain of thecompound (A).

Examples of the compound (A) include a modified polyphenylene ethercompound having the group represented by Formula (1) at the terminal ofthe molecule and a polymer having a structural unit represented by thefollowing Formula (5) in the molecule.

In Formula (5), Z represents an arylene group. R₁ to R₃ are independentof each other. In other words, R₁ to R₃ may be the same group as ordifferent groups from each other. R₁ to R₃ represent a hydrogen atom oran alkyl group. R₆ to R₈ are independent of each other. In other words,R₆ to R₈ may be the same group as or different groups from each other.R₆ to R₈ represent a hydrogen atom or an alkyl group having 1 to 6carbon atoms.

As described above, the compound (A) is only required to have the grouprepresented by Formula (1), and the atom to which this group is bondedis not particularly limited and may be, for example, an oxygen atom or acarbon atom. Specifically, in the case of the modified polyphenyleneether compound, examples of the atom to which the group represented byFormula (1) is bonded include an oxygen atom at the terminal of the mainchain. In the case of a polymer having a structural unit represented byFormula (5) in the molecule, examples of the atom to which the grouprepresented by Formula (1) is bonded include carbon atoms constitutingthe main chain as represented by Formula (5). As the compound (A), thesemay be used singly or both of these may be used in combination.

(Modified Polyphenylene Ether Compound)

The modified polyphenylene ether compound is not particularly limited aslong as it is a modified polyphenylene ether compound having the grouprepresented by Formula (1) at the terminal of the molecule. Specificpreferred examples of the group represented by Formula (1) include agroup represented by the following Formula (11).

More specific examples of the substituent containing the vinylbenzylgroup include vinylbenzyl groups (ethenylbenzyl groups) such as ap-ethenylbenzyl group and a m-ethenylbenzyl group and a vinylphenylgroup.

The modified polyphenylene ether compound has a polyphenylene etherchain in the molecule and preferably has, for example, a structural unitrepresented by the following Formula (12) in the molecule.

In Formula (12), m represents 1 to 50. R₁₄ to R₁₇ are independent ofeach other. In other words, R₁₄ to R₁₇ may be the same group as ordifferent groups from each other. R₁₄ to R₁₇ represent a hydrogen atom,an alkyl group, an alkenyl group, an alkynyl group, a formyl group, analkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonylgroup. Among these, a hydrogen atom and an alkyl group are preferable.

Specific examples of the respective functional groups mentioned in R₁₄to R₁₇ include the following.

The alkyl group is not particularly limited and is, for example,preferably an alkyl group having 1 to 18 carbon atoms, more preferablyan alkyl group having 1 to 10 carbon atoms. Specific examples thereofinclude a methyl group, an ethyl group, a propyl group, a hexyl group,and a decyl group.

The alkenyl group is not particularly limited and is, for example,preferably an alkenyl group having 2 to 18 carbon atoms, more preferablyan alkenyl group having 2 to 10 carbon atoms. Specific examples thereofinclude a vinyl group, an allyl group, and a 3-butenyl group.

The alkynyl group is not particularly limited and is, for example,preferably an alkynyl group having 2 to 18 carbon atoms, more preferablyan alkynyl group having 2 to 10 carbon atoms. Specific examples thereofinclude an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

The alkylcarbonyl group is not particularly limited as long as it is acarbonyl group substituted with an alkyl group and is, for example,preferably an alkylcarbonyl group having 2 to 18 carbon atoms, morepreferably an alkylcarbonyl group having 2 to 10 carbon atoms. Specificexamples thereof include an acetyl group, a propionyl group, a butyrylgroup, an isobutyryl group, a pivaloyl group, a hexanoyl group, anoctanoyl group, and a cyclohexylcarbonyl group.

The alkenylcarbonyl group is not particularly limited as long as it is acarbonyl group substituted with an alkenyl group and is, for example,preferably an alkenylcarbonyl group having 3 to 18 carbon atoms, morepreferably an alkenylcarbonyl group having 3 to 10 carbon atoms.Specific examples thereof include an acryloyl group, a methacryloylgroup, and a crotonoyl group.

The alkynylcarbonyl group is not particularly limited as long as it is acarbonyl group substituted with an alkynyl group and is, for example,preferably an alkynylcarbonyl group having 3 to 18 carbon atoms, morepreferably an alkynylcarbonyl group having 3 to 10 carbon atoms.Specific examples thereof include a propioloyl group.

Examples of the modified polyphenylene ether compound include a modifiedpolyphenylene ether compound represented by the following Formula (13)and a modified polyphenylene ether compound represented by the followingFormula (14). Moreover, as the modified polyphenylene ether compound,these modified polyphenylene ether compounds may be used singly or twokinds of these modified polyphenylene ether compounds may be used incombination.

In Formulas (13) and (14), R₁₈ to R₂₅ and R₂₆ to R₃₃ each independentlyrepresent a hydrogen atom, an alkyl group, an alkenyl group, an alkynylgroup, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group,or an alkynylcarbonyl group. X₁ and X₂ each independently represent agroup represented by Formula (1). A and B each represent structuralunits represented by the following Formulas (15) and (16). In Formula(14), Y represents a linear, branched, or cyclic hydrocarbon having 20or less carbon atoms.

In Formulas (15) and (16), s and t each represent 0 to 20. R₃₄ to R₃₇and R₃₈ to R₄₁ each independently represent a hydrogen atom, an alkylgroup, an alkenyl group, an alkynyl group, a formyl group, analkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonylgroup.

The modified polyphenylene ether compound represented by Formula (13)and the modified polyphenylene ether compound represented by Formula(14) are not particularly limited as long as they satisfy the aboveconfiguration. Specifically, in Formulas (13) and (14), R₁₈ to R₂₅ andR₂₆ to R₃₃ are independent of each other as described above. In otherwords, R₁₈ to R₂₅ and R₂₆ to R₃₃ may be the same group as or differentgroups from each other. R₁₈ to R₂₅ and R₂₆ to R₃₃ represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, a formylgroup, an alkylcarbonyl group, an alkenylcarbonyl group, or analkynylcarbonyl group. Among these, a hydrogen atom and an alkyl groupare preferable.

In Formulas (15) and (16), sand teach preferably represent 0 to 20 asdescribed above. It is preferable that s and t represent numericalvalues so that the sum of s and t is 1 to 30. Hence, it is morepreferable that s represents 0 to 20, t represents 0 to 20, and the sumof s and t represents 1 to 30. R₃₄ to R₃₇ and R₃₈ to R₄₁ are independentof each other. In other words, R₃₄ to R₃₇ and R₃₈ to R₄₁ may be the samegroup as or different groups from each other. R₃₄ to R₃₇ and R₃₈ to R₄₁represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynylgroup, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group,or an alkynylcarbonyl group. Among these, a hydrogen atom and an alkylgroup are preferable.

R₁₈ to R₄₁ are the same as R₁₄ to R₁₇ in Formula (12).

In Formula (14), Y represents a linear, branched, or cyclic hydrocarbonhaving 20 or less carbon atoms as described above. Examples of Y includea group represented by the following Formula (17).

In Formula (17), R₄₂ and R₄₃ each independently represent a hydrogenatom or an alkyl group. Examples of the alkyl group include a methylgroup. Examples of the group represented by Formula (17) include amethylene group, a methylmethylene group, and a dimethylmethylene group.Among these, a dimethylmethylene group is preferable.

More specific examples of the modified polyphenylene ether compoundrepresented by Formula (13) include a modified polyphenylene ethercompound represented by the following Formula (18).

More specific examples of the modified polyphenylene ether compoundrepresented by Formula (14) include a modified polyphenylene ethercompound represented by the following Formula (19)

In Formulas (18) and (19), sand tare the same as s and t in Formulas(15) and (16). In Formulas (18) and (19), R₁ to R₃ and n are the same asR₁ to R₃ and n in Formula (1). In Formula (19), Y is the same as Y inFormula (14).

(Polymer Having Structural Unit Represented by Formula (5) in Molecule)

The polymer is not particularly limited as long as it is a polymerhaving the structural unit represented by Formula (5) in the molecule.The polymer may have a structural unit other than the structural unitrepresented by Formula (5) as long as it is a polymer having thestructural unit represented by Formula (5) in the molecule. The polymermay include a repeating unit in which the structural unit represented byFormula (5) is repeatedly bonded, or the polymer may be a polymer inwhich a repeating unit in which the structural unit represented byFormula (5) is repeatedly bonded and a repeating unit in which astructural unit other than the structural unit represented by Formula(5) is repeatedly bonded are randomly bonded. In other words, thepolymer may be a block copolymer or a random copolymer when the polymerhas a structural unit other than the structural unit represented byFormula (5).

The arylene group in Formula (5) is not particularly limited. Examplesof this arylene group include a monocyclic aromatic group such as aphenylene group, and a polycyclic aromatic group in which the aromaticis not a single ring but a polycyclic aromatic such as a naphthalenering. This arylene group also includes a derivative in which a hydrogenatom bonded to an aromatic ring is substituted with a functional groupsuch as an alkenyl group, an alkynyl group, a formyl group, analkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonylgroup.

The alkyl group represented by R₁ to R₃ in Formula (5) is similar to thealkyl group represented by R₁ to R₃ in Formula (1). In other words, thealkyl group represented by R₁ to R₃ in Formula (5) is not particularlylimited, and for example, an alkyl group having 1 to 18 carbon atoms ispreferable and an alkyl group having 1 to 10 carbon atoms is morepreferable. Specific examples thereof include a methyl group, an ethylgroup, a propyl group, a hexyl group, and a decyl group.

The alkyl group having 1 to 6 carbon atoms represented by R₆ to R₈ inFormula (5) is not particularly limited, and specific examples thereofinclude a methyl group, an ethyl group, a propyl group, and a hexylgroup.

It is preferable that the polymer includes an aromatic polymer having astructural unit derived from a bifunctional aromatic compound in whichtwo carbon-carbon unsaturated double bonds are bonded to an aromaticring as the structural unit represented by Formula (5). The structuralunit derived from a bifunctional aromatic compound is a structural unitobtained by polymerizing the bifunctional aromatic compound. In thepresent specification, the aromatic polymer is also referred to as adivinyl aromatic polymer.

The bifunctional aromatic compound is not particularly limited as longas it is a bifunctional aromatic compound in which two carbon-carbonunsaturated double bonds are bonded to an aromatic ring. Examples of thebifunctional aromatic compound include m-divinylbenzene,p-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene,1,4-diisopropenylbenzene, 1,3-divinylnaphthalene,1,8-divinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene,2,3-divinylnaphthalene, 2,7-divinylnaphthalene, 2,6-divinylnaphthalene,4,4′-divinylbiphenyl, 4,3′-divinylbiphenyl, 4,2′-divinylbiphenyl,3,2′-divinylbiphenyl, 3,3′-divinylbiphenyl, 2,2′-divinylbiphenyl,2,4-divinylbiphenyl, 1,2-divinyl-3,4-dimethylbenzene,1,3-divinyl-4,5,8-tributylnaphthalene, and 2,2′-divinyl4-ethyl-4′-propylbiphenyl. These may be used singly or in combination oftwo or more kinds thereof. Among these, the bifunctional aromaticcompound is preferably divinylbenzene such as m-divinylbenzene andp-divinylbenzene, more preferably p-divinylbenzene.

The aromatic polymer may have not only a structural unit derived fromthe bifunctional aromatic compound but also another structural unit.Examples of the other structural unit include a structural unit derivedfrom a monofunctional aromatic compound in which one carbon-carbonunsaturated double bond is bonded to an aromatic ring, a structural unitderived from a trifunctional aromatic compound in which threecarbon-carbon unsaturated double bonds are bonded to an aromatic ring,structural units derived from indenes, and structural units derived fromacenaphthylenes. The structural unit derived from a monofunctionalaromatic compound is a structural unit obtained by polymerizing themonofunctional aromatic compound. The structural unit derived from atrifunctional aromatic compound is a structural unit obtained bypolymerizing the trifunctional aromatic compound. The structural unitsderived from indenes are structural units obtained by polymerizingindenes. The structural units derived from acenaphthylenes arestructural units obtained by polymerizing acenaphthylenes.

In the monofunctional aromatic compound, it is only required that onecarbon-carbon unsaturated double bond is bonded to an aromatic ring, anda group other than the carbon-carbon unsaturated double bond may bebonded to the aromatic ring. Examples of the monofunctional aromaticcompound include a monofunctional aromatic compound in which onecarbon-carbon unsaturated double bond is bonded to an aromatic ring anda group other than this carbon-carbon unsaturated double bond is notbonded the aromatic ring and a monofunctional aromatic compound in whichone carbon-carbon unsaturated double bond is bonded to an aromatic ringand an alkyl group such as an ethyl group is further bonded to thearomatic ring.

Examples of the monofunctional aromatic compound in which onecarbon-carbon unsaturated double bond is bonded to an aromatic ring anda group other than this carbon-carbon unsaturated double bond is notbonded the aromatic ring include styrene, 2-vinylbiphenyl,3-vinylbiphenyl, 4-vinylbiphenyl, 1-vinylnaphthalene,2-vinylnaphthalene, and α-alkyl-substituted styrene. Examples of theα-alkyl-substituted styrene include α-methylstyrene, α-ethylstyrene,α-propylstyrene, α-n-butylstyrene, α-isobutylstyrene, α-t-butylstyrene,α-n-pentylstyrene, α-2-methylbutylstyrene, α-3-methylbutyl-2-styrene,α-t-butylstyrene, α-t-butylstyrene, α-n-pentylstyrene,α-2-methylbutylstyrene, α-3-methylbutylstyrene, α-t-pentylstyrene,α-n-hexylstyrene, α-2-methylpentylstyrene, α-3-methylpentylstyrene,α-1-methylpentylstyrene, α-2,2-dimethylbutylstyrene,α-2,3-dimethylbutylstyrene, α-2,4-dimethylbutylstyrene,α-3,3-dimethylbutylstyrene, α-3,4-dimethylbutylstyrene,α-4,4-dimethylbutylstyrene, α-2-ethylbutylstyrene,α-1-ethylbutylstyrene, α-cyclohexylstyrene, and α-cyclohexylstyrene.These may be used singly or in combination of two or more kinds thereof.

Examples of monofunctional aromatic compounds in which one carbon-carbonunsaturated double bond is bonded to an aromatic ring and an alkyl groupis further bonded to the aromatic ring include a nuclearalkyl-substituted aromatic compound and alkoxy-substituted styrene.

Examples of the nuclear alkyl-substituted aromatic compound include anethyl vinyl aromatic compound in which an alkyl group bonded to anaromatic ring is an ethyl group, nuclear alkyl-substituted styrene inwhich an alkyl group is bonded to styrene as an aromatic ring, andnuclear alkyl-substituted aromatic compounds (other nuclearalkyl-substituted aromatic compounds) other than the ethyl vinylaromatic compound and the nuclear alkyl-substituted styrene.

Examples of the ethyl vinyl aromatic compound include o-ethyl vinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene,2-vinyl-2′-ethylbiphenyl, 2-vinyl-3′-ethylbiphenyl,2-vinyl-4-ethylbiphenyl, 3-vinyl-2′-ethylbiphenyl,3-vinyl-3′-ethylbiphenyl, 3-vinyl-4′-ethylbiphenyl,4-vinyl-2′-ethylbiphenyl, 4-vinyl-3′-ethylbiphenyl,4-vinyl-4′-ethylbiphenyl, 1-vinyl-2-ethylnaphthalene,1-vinyl-3-ethylnaphthalene, 1-vinyl-4-ethylnaphthalene,1-vinyl-5-ethylnaphthalene, 1-vinyl-6-ethylnaphthalene,1-vinyl-7-ethylnaphthalene, 1-vinyl-8-ethylnaphthalene,2-vinyl-1-ethylnaphthalene, 2-vinyl-3-ethylnaphthalene,2-vinyl-4-ethylnaphthalene, 2-vinyl-5-ethylnaphthalene,2-vinyl-6-ethylnaphthalene, 2-vinyl-7-ethylnaphthalene, and2-vinyl-8-ethylnaphthalene.

Examples of the nuclear alkyl-substituted styrene includem-methylstyrene, p-methylstyrene, m-propylstyrene, p-propylstyrene,m-n-butylstyrene, p-n-butylstyrene, m-t-butylstyrene, p-t-butylstyrene,m-n-hexylstyrene, p-n-hexylstyrene, m-cyclohexylstyrene, andp-cyclohexylstyrene.

Examples of the other nuclear alkyl-substituted aromatic compoundsinclude 2-vinyl-2′-propylbiphenyl, 2-vinyl-3′-propylbiphenyl,2-vinyl-4′-propylbiphenyl, 3-vinyl-2′-propylbiphenyl,3-vinyl-3′-propylbiphenyl, 3-vinyl-4′-propylbiphenyl,4-vinyl-2′-propylbiphenyl, 4-vinyl-3′-propylbiphenyl,4-vinyl-4′-propylbiphenyl, 1-vinyl-2-propylnaphthalene,1-vinyl-3-propylnaphthalene, 1-vinyl-4-propylnaphthalene,1-vinyl-5-propylnaphthalene, 1-vinyl-6-propylnaphthalene,1-vinyl-7-propylnaphthalene, 1-vinyl-8-propylnaphthalene,2-vinyl-1-propylnaphthalene, 2-vinyl-3-propylnaphthalene,2-vinyl-4-propylnaphthalene, 2-vinyl-5-propylnaphthalene,2-vinyl-6-propylnaphthalene, 2-vinyl-7-propylnaphthalene, and2-vinyl-8-propylnaphthalene.

Examples of the alkoxy-substituted styrene include o-ethoxystyrene,m-ethoxystyrene, p-ethoxystyrene, o-propoxystyrene, m-propoxystyrene,p-propoxystyrene, o-n-butoxystyrene, m-n-butoxystyrene,p-n-butoxystyrene, o-isobutoxystyrene, m-isobutoxystyrene,p-isobutoxystyrene, o-t-butoxystyrene, m-t-butoxystyrene,p-t-butoxystyrene, o-n-pentoxystyrene, m-n-pentoxystyrene,p-n-pentoxystyrene, α-methyl-o-butoxystyrene, α-methyl-m-butoxystyrene,α-methyl-p-butoxystyrene, o-t-pentoxystyrene, m-t-pentoxystyrene,p-t-pentoxystyrene, o-n-hexoxystyrene, n-n-hexoxystyrene,p-n-hexoxystyrene, α-methyl-o-pentoxystyrene, α-methyl-m-pentoxystyrene,α-methyl-p-pentoxystyrene, o-cyclohexoxystyrene, m-cyclohexoxystyrene,p-cyclohexoxystyrene, o-phenoxystyrene, m-phenoxystyrene, andp-phenoxystyrene.

As the monofunctional aromatic compound, the compounds exemplified abovemay be used singly or in combination of two or more kinds thereof. Amongthe compounds exemplified above, styrene and p-ethylvinylbenzene arepreferable as the monofunctional aromatic compound.

Examples of the trifunctional aromatic compound in which threecarbon-carbon unsaturated double bonds are bonded to an aromatic ringinclude 1,2,4-trivinylbenzene, 1,3,5-trivinylbenzene,1,2,4-triisopropenylbenzene, 1,3,5-triisopropenylbenzene,1,3,5-trivinylnaphthalene, and 3,5,4′-trivinylbiphenyl. As thetrifunctional aromatic compound, the compounds exemplified above may beused singly or in combination of two or more kinds thereof.

Examples of the indenes include indene, alkyl-substituted indene, andalkoxyindene. Examples of the alkyl-substituted indene includemethylindene, ethylindene, propylindene, butylindene, t-butylindene,sec-butylindene, n-pentylindene, 2-methyl-butylindene,3-methyl-butylindene, n-hexylindene, 2-methyl-pentylindene,3-methyl-pentylindene, and 4-methyl-pentylindene. Examples of thealkyloxyindene include alkyloxyindenes such as methoxyindene,ethoxyindene, propoxyindene, butoxyindene, t-butoxyindene,sec-butoxyindene, n-pentoxyindene, 2-methyl-butoxyindene,3-methyl-butoxyindene, n-hexoxyindene, 2-methyl-pentoxyindene,3-methyl-pentoxyindene, and 4-methyl-pentoxyindene. As the indenes, thecompounds exemplified above may be used singly or in combination of twoor more kinds thereof.

Examples of the acenaphthylenes include acenaphthylene,alkylacenaphthylenes, halogenated acenaphthylenes, andphenylacenaphthylenes. Examples of the alkyl acenaphthylenes include1-methyl acenaphthylene, 3-methyl acenaphthylene, 4-methylacenaphthylene, 5-methyl acenaphthylene, 1-ethyl acenaphthylene, 3-ethylacenaphthylene, 4-ethyl acenaphthylene, and 5-ethyl acenaphthylene.Examples of the halogenated acenaphthylenes include1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene,5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene,4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of thephenylacenaphthylenes include 1-phenylacenaphthylene,3-phenylacenaphthylene, 4-phenylacenaphthylene, and5-phenylacenaphthylene. As the acenaphthylenes, the compoundsexemplified above may be used singly or in combination of two or morekinds thereof.

When the aromatic polymer has not only a structural unit derived fromthe bifunctional aromatic compound but also another structural unit, thearomatic polymer is a copolymer of a structural unit derived from thebifunctional aromatic compound and another structural unit such as astructural unit derived from the monofunctional aromatic compound. Thiscopolymer may be a block copolymer or a random copolymer.

The polymer is not particularly limited as long as it is a polymerhaving the structural unit represented by Formula (5) in the molecule asdescribed above. It is preferable that the structural unit representedby Formula (5) includes a structural unit represented by the followingFormula (6). In other words, the polymer is preferably a polymer havinga structural unit represented by the following Formula (6) in themolecule.

R₆ to R₈ in Formula (6) are similar to R₆ to R₈ in Formula (5).Specifically, R₆ to R₈ each independently represent a hydrogen atom oran alkyl group having 1 to 6 carbon atoms. R₉ represents an arylenegroup having 6 to 12 carbon atoms.

The arylene group having 6 to 12 carbon atoms in Formula (6) is notparticularly limited. Examples of this arylene group include amonocyclic aromatic group such as a phenylene group and a bicyclicaromatic group in which the aromatic is not a monocyclic ring but abicyclic aromatic such as a naphthalene ring. This arylene group alsoincludes a derivative in which a hydrogen atom bonded to an aromaticring is substituted with a functional group such as an alkenyl group, analkynyl group, a formyl group, an alkylcarbonyl group, analkenylcarbonyl group, or an alkynylcarbonyl group.

It is preferable that the structural unit represented by Formula (6)includes a structural unit represented by the following Formula (7). Inother words, in the structural unit represented by Formula (6), R₉ ispreferably a phenylene group. Among the phenylene groups, a p-phenylenegroup is more preferable.

R₆ to R₈ in Formula (7) are similar to R₆ to R₈ in Formula (5).Specifically, R₆ to R₈ each independently represent a hydrogen atom oran alkyl group having 1 to 6 carbon atoms.

The polymer preferably

includes a polymer having a structural unit represented by the followingFormula (8) in the molecule. In other words, it is preferable that thepolymer has a structural unit derived from a monofunctional aromaticcompound in which one carbon-carbon unsaturated double bond is bonded toan aromatic ring as the structural unit represented by the followingFormula (8). Hence, the polymer is preferably a polymer having astructural unit represented by Formula (5) and a structural unitrepresented by the following Formula (8) in the molecule. In otherwords, the polymer may have a structural unit other than the structuralunit represented by Formula (5) and the structural unit represented bythe following Formula (8) (structural unit other than (5) and (8)) aslong as it is a polymer having a structural unit represented by Formula(5) and the structural unit represented by the following Formula (8) inthe molecule. The polymer may include a structural unit other than (5)and (8), the polymer may be a polymer in which a repeating unit in whichthe structural unit represented by Formula (5) is repeatedly bonded, arepeating unit in which the structural unit represented by the followingFormula (8) is repeatedly bonded, and a repeating unit in which astructural unit other than (5) and (8) is repeatedly bonded are randomlybonded, or the polymer may be a block copolymer or a random copolymer.

In Formula (8), R₁₀ to R₁₂ are independent of each other. In otherwords, R₁₀ to R₁₂ may be the same group as or different groups from eachother. R₁₀ to R₁₂ represent a hydrogen atom or an alkyl group having 1to 6 carbon atoms. R₁₃ represents an aryl group.

The alkyl group having 1 to 6 carbon atoms represented by R₁₀ to R₁₂ inFormula (8) is not particularly limited and may be similar to the alkylgroup having 1 to 6 carbon atoms represented by R₆ to R₈ in Formula (5).Specific examples of the alkyl group having 1 to 6 carbon atomsrepresented by R₁₀ to R₁₂ in Formula (8) include a methyl group, anethyl group, a propyl group, and a hexyl group.

The aryl group in Formula (8) is not particularly limited and may be anunsubstituted aryl group or an aryl group in which a hydrogen atombonded to an aromatic ring is substituted with an alkyl group or thelike. The unsubstituted aryl group may be a group obtained byeliminating one hydrogen atom from an aromatic hydrocarbon having onearomatic ring or a group obtained by eliminating one hydrogen atom froman aromatic hydrocarbon having two or more independent aromatic rings(for example, biphenyl). Examples of the aryl group in Formula (8)include an unsubstituted aryl group having 6 to 12 carbon atoms and anarylene group having 6 to 18 carbon atoms in which a hydrogen atom of anaryl group having 6 to 12 carbon atoms is substituted with an alkylgroup having 1 to 6 carbon atoms. Examples of the unsubstituted arylgroup having 6 to 12 carbon atoms include a phenyl group, a naphthylgroup, and a biphenylyl group. Specific examples of the aryl group inFormula (8), namely, R₁₃ include the aryl groups presented in thefollowing Tables 1 and 2.

TABLE 1

TABLE 2

The compound (A) is only required to be a compound having at least onegroup represented by Formula (1) in the molecule and may be, forexample, the modified polyphenylene ether compound or the polymer, andthe modified polyphenylene ether compound and the polymer may be usedconcurrently.

The weight average molecular weight of the compound (A) is preferably1,500 to 40,000, more preferably 1,500 to 35,000. When the weightaverage molecular weight is too low, the heat resistance and the liketend to decrease. When the weight average molecular weight is too high,the moldability and the like tend to decrease. Hence, when the weightaverage molecular weight of the resin composition is within the aboverange, excellent heat resistance and moldability are exhibited. Here,the weight average molecular weight is only required to be one measuredby general molecular weight measurement, and specific examples thereofinclude a value measured by gel permeation chromatography (GPC).

In the polymer, when the sum of structural units in the polymer is 100mol %, the molar content of the structural unit represented by Formula(5) is preferably a molar content within the range of the weight averagemolecular weight. Specifically, the molar content is preferably 2 to 95mol %, more preferably 8 to 81 mol %. The molar content of thestructural unit represented by Formula (6) and the molar content of thestructural unit represented by Formula (7) are similar to the molarcontent of the structural unit represented by Formula (5). Specifically,the molar contents are preferably 2 to 95 mol %, more preferably 8 to 81mol %. When the polymer is a polymer having a structural unitrepresented by Formula (5) and a structural unit represented by Formula(8) in the molecule, the molar content of the structural unitrepresented by Formula (5) is preferably 2 to 95 mol %, more preferably8 to 81 mol % and the molar content of the structural unit representedby Formula (8) is preferably 5 to 98 mol %, more preferably 19 to 92 mol%.

In the polymer, the average number of structural units represented byFormula (5) is preferably a number within the range of the weightaverage molecular weight. Specifically, the average number is preferably1 to 160, more preferably 3 to 140. The average number of structuralunits represented by Formula (6) and the average number of structuralunits represented by Formula (7) are similar to the average number ofstructural units represented by Formula (5). Specifically, the averagenumber is preferably 1 to 160, more preferably 3 to 140. When thepolymer is a polymer having a structural unit represented by Formula (5)and a structural unit represented by Formula (8) in the molecule, theaverage number of structural units represented by Formula (5) ispreferably 1 to 160, more preferably 3 to 140 and the average number ofstructural units represented by Formula (8) is preferably 2 to 350, morepreferably 4 to 300.

Specific examples of the polymer include a polymer having a structuralunit represented by the following Formula (21) in the molecule andfurther at least either of a structural unit represented by thefollowing Formula (20) or a structural unit represented by the followingFormula (22). This polymer may be a block copolymer or a randomcopolymer.

In the polymer having the structural unit represented by Formula (21) inthe molecule and further at least either of the structural unitrepresented by Formula (20) or the structural unit represented byFormula (22), the molar contents of the structural unit represented byFormula (20), the structural unit represented by Formula (21), and thestructural unit represented by Formula (22) are preferably 0 to 92 mol%, 8 to 54 mol %, and 0 to 89 mol %, respectively. The average number ofstructural units represented by Formula (20) is preferably 0 to 350, theaverage number of structural units represented by Formula (21) ispreferably 1 to 160, and the average number of structural unitsrepresented by Formula (22) is preferably 0 to 270. As the polymer, forexample, commercially available products such as ODV-XET(X03),ODV-XET(X04), and ODV-XET(X05) manufactured by NIPPON STEEL Chemical &Materials Co., Ltd. are used.

The equivalent of the vinyl group included in the group that isrepresented by Formula (1) and contains a hydrogen atom as R₁ to R₃ inthe compound (A) is preferably 250 to 1200, more preferably 300 to 1100.When the equivalent is too small, the number of groups represented byFormula (1) is too large, the reactivity is too high, and for example,troubles such as deterioration in the storage stability of the resincomposition or deterioration in the fluidity of the resin compositionmay occur. When a resin composition in which the equivalent is too smallis used, for example, molding defects such as generation of voids at thetime of multilayer molding may occur by insufficient fluidity and thelike and a problem with moldability that a highly reliable wiring boardis hardly obtained may occur. When the equivalent is too large, thenumber of the groups represented by Formula (1) is too small and theheat resistance of the cured product tends to be insufficient. Hence,when the equivalent of the group represented by Formula (1) in the resincomposition is within the above range, excellent heat resistance andmoldability are exhibited. The equivalent of the vinyl group included inthe group that is represented by Formula (1) and contains a hydrogenatom as R₁ to R₃ is a so-called vinyl equivalent.

(Crosslinking Type Curing Agent (B))

The crosslinking type curing agent (B) is not particularly limited aslong as it is a curing agent which reacts with the compound (A), iscrosslinked with the compound (A), and thus can cure the resincomposition. Examples of the crosslinking type curing agent (B) includea compound having two or more unsaturated double bonds in the molecule,an alkenyl isocyanurate compound, styrene, a styrene derivative, anallyl compound having at least one or more allyl groups in the molecule,a maleimide compound having at least one or more maleimide groups in themolecule, a modified maleimide compound, and an acenaphthylene compoundhaving an acenaphthylene structure in the molecule. Examples of thecompound having two or more unsaturated double bonds in the moleculeinclude a polyfunctional methacrylate compound having two or moremethacryloyl groups in the molecule, a polyfunctional acrylate compoundhaving two or more acryloyl groups in the molecule, and a polyfunctionalvinyl compound having two or more vinyl groups in the molecule. Examplesof the polyfunctional vinyl compound include divinylbenzene andpolybutadiene. The alkenyl isocyanurate compound is only required to bea compound having an isocyanurate structure and an alkenyl group in themolecule, and examples thereof include trialkyl isocyanurate compoundssuch as triallyl isocyanurate (TAIC). Examples of the styrene derivativeinclude bromostyrene. Examples of the modified maleimide compoundinclude a modified maleimide compound in which a part of the molecule isamine-modified, a modified maleimide compound in which a part of themolecule is silicone-modified, and a modified maleimide compound inwhich a part of the molecule is amine-modified and silicone-modified.Among these, the alkenyl isocyanurate compound, the polyfunctionalacrylate compound, the polyfunctional methacrylate compound, and thepolyfunctional vinyl compound are preferable from the viewpoint that theheat resistance of the cured product of the resin composition can befurther enhanced. It is considered that this is because crosslinking ofthe resin composition is more suitably formed by the curing reactionwhen using these crosslinking type curing agents. As the crosslinkingtype curing agent, the crosslinking type curing agents exemplified maybe used singly or in combination of two or more kinds thereof. As thecrosslinking type curing agent, not only the crosslinking type curingagents exemplified above such as the compound having two or moreunsaturated double bonds in the molecule but also a compound having oneunsaturated double bond in the molecule may be used concurrently.Examples of the compound having one unsaturated double bond in themolecule include a monovinyl compound having one vinyl group in themolecule.

Examples of the polyfunctional methacrylate compound include a compoundhaving a polyphenylene ether structure and two or more methacryloylgroups in the molecule and tricyclodecane dimethanol dimethacrylate.Examples of the compound having a polyphenylene ether structure and twoor more methacryloyl groups in the molecule include a methacryl-modifiedpolyphenylene ether compound obtained by modifying the terminal hydroxylgroup of polyphenylene ether with a methacryl group. Specific examplesthereof include compounds in which the substituents at the X₁ and X₂moieties of the modified polyphenylene ether compound represented byFormula (13) or the modified polyphenylene ether compound represented byFormula (14) are substituted with a methacryloyl group. More specificexamples of this methacryl-modified polyphenylene ether compound includea compound represented by the following Formula (23).

In Formula (23), s and t are the same as s and t in Formulas (15) and(16). In Formula (23), Y is the same as Y in Formula (14).

As the crosslinking type curing agent (B), for example, styrene,divinylbenzene, trialkenyll isocyanurate compounds such as triallylisocyanurate (TAIC), a polybutadiene compound, a maleimide compound, andan acenaphthylene compound are also preferably used. Among these, amaleimide compound is preferable, and a monofunctional maleimidecompound having one maleimide group in the molecule is more preferable.Specific preferred examples of the monofunctional maleimide compoundinclude a compound represented by the following Formula 9) and acompound represented by the following Formula (10).

The acenaphthylene compound is not particularly limited as long as it isa compound having an acenaphthylene skeleton, and examples thereofinclude acenaphthylene and acenaphthylene derivatives. Specific examplesof the acenaphthylene compound include an acenaphthylene, ahydroxyacenaphthylene compound, an alkyl acenaphthylene compound, analkoxy acenaphthylene compound, and a halogenated acenaphthylenecompound. Examples of the hydroxyacenaphthylene compound include3-hydroxyacenaphthylene, 4-hydroxyacenaphthylene,5-hydroxyacenaphthylene, and 5,6-dihydroxyacenaphthylene. Examples ofthe alkyl acenaphthylene compound include 3-methylacenaphthylene,3-ethylacenaphthylene, 3-propylacenaphthylene, 4-methylacenaphthylene,4-ethylacenaphthylene, 4-propylacenaphthylene, 5-methylacenaphthylene,5-ethylacenaphthylene, 5-propylacenaphthylene,3,8-dimethylacenaphthylene, and 5,6-dimethylacenaphthylene compound.Examples of the alkoxy acenaphthylene compound include3-methoxyacenaphthylene, 3-ethoxyacenaphthylene, 3-butoxyacenaphthylene,4-methoxyacenaphthylene, 4-ethoxyacenaphthylene, 4-butoxyacenaphthylene,5-methoxyacenaphthylene, 5-ethoxyacenaphthylene, and5-butoxyacenaphthylene. Examples of the halogenated acenaphthylenecompound include 3-chloroacenaphthylene, 3-bromoacenaphthylene,4-chloroacenaphthylene, 4-bromoacenaphthylene, 5-chloroacenaphthylene,and 5-bromoacenaphthylene.

(Azo Compound (C))

The azo compound (C) is not particularly limited as long as it has anazo group in the molecule and has no heteroatom other than the nitrogenatom constituting the azo group. Specific examples of the azo compound(C) include the azo initiator represented by Formula (2).[Chem. 22]R₄—N═N—R₅  (2)

In Formula (2), R₄ and R₅ are independent of each other. In other words,R₄ and R₅ may be the same group as or different groups from each other.R₄ and R₅ represent a hydrogen atom or an alkyl group. The alkyl groupof R₄ and R₅ may be a linear alkyl group or a branched alkyl group. Thealkyl group of R₄ and R₅ preferably has 1 to 8 carbon atoms.

The linear alkyl group is only required to be linear and has preferably1 to 8 carbon atoms, preferably 4 to 8 carbon atoms. Specific examplesof the linear alkyl group include a butyl group, a pentyl group, a hexylgroup, and an octyl group.

The branched alkyl group is only required to be branched and haspreferably 3 to 8 carbon atoms, more preferably 4 to 8 carbon atoms.Specific examples of the branched alkyl group include a t-butyl groupand a 2,2′,4,4′-tetramethylbutyl group.

The azo compounds (C) may be used singly or in combination of two kindsor more thereof. Specific preferred examples of the azo compound (C)include a compound represented by the following Formula (3) and acompound represented by the following Formula (4).

(Content)

The content of the compound (A) is preferably 50 to 90 parts by mass,more preferably 60 to 80 parts by mass with respect to 100 parts by massof the total mass of the compound (A) and the crosslinking type curingagent (B). The content of the crosslinking type curing agent (B) ispreferably 10 to 50 parts by mass, more preferably 20 to 40 parts bymass with respect to 100 parts by mass of the total mass of the compound(A) and the crosslinking type curing agent (B). The content of the azocompound (C) is preferably 0.01 to 2 parts by mass, more preferably 0.1to 1 part by mass with respect to 100 parts by mass of the total mass ofthe compound (A) and the crosslinking type curing agent (B). When thecontents of the compound (A), the crosslinking type curing agent (B),and the azo compound (C) are within the above ranges, the obtained resincomposition can suitably provide a cured product exhibiting lowdielectric properties and high heat resistance. Among the contents ofthe compound (A), the crosslinking type curing agent (B), and the azocompound (C), for example, when the content of the azo compound (C) istoo large, the heat resistance tends to decrease.

When the compound (A) contains the polymer, the content ratio of thepolymer to the acenaphthylene compound (B) is preferably 50:50 to 95:5,more preferably 60:40 to 95:5 in terms of mass ratio.

When the compound (A) is concurrently used with the modifiedpolyphenylene ether compound and the polymer, the content of themodified polyphenylene ether compound is preferably 5 to 50 parts bymass, more preferably 5 to 40 parts by mass with respect to 100 parts bymass of the sum of the modified polyphenylene ether compound, thepolymer, and the acenaphthylene compound (B). The content of the polymeris preferably 20 to 95 parts by mass, more preferably 30 to 70 parts bymass with respect to 100 parts by mass of the sum of the modifiedpolyphenylene ether compound, the polymer, and the acenaphthylenecompound (B).

(Other Components)

The resin composition according to the present embodiment may containcomponents (other components) other than the compound (A), thecrosslinking type curing agent (B), and the azo compound (C) ifnecessary as long as the effects of the present invention are notimpaired. As the other components to be contained in the resincomposition according to the present embodiment, for example, additivessuch as a silane coupling agent, a flame retardant, a defoaming agent,an antioxidant, a heat stabilizer, an antistatic agent, an ultravioletabsorber, a dye and a pigment, a lubricant, and an inorganic filler maybe further contained. The resin composition may contain thermosettingresins such as an epoxy resin, an unsaturated polyester resin, and athermosetting polyimide resin in addition to the compound (A).

As described above, the resin composition according to the presentembodiment may contain a silane coupling agent. The silane couplingagent may be contained in the resin composition or may be contained as asilane coupling agent covered on the inorganic filler to be contained inthe resin composition for surface treatment in advance. Among these, itis preferable that the silane coupling agent is contained as a silanecoupling agent covered on the inorganic filler for surface treatment inadvance, and it is more preferable that the silane coupling agent iscontained as a silane coupling agent covered on the inorganic filler forsurface treatment in advance and further is also contained in the resincomposition. In the case of a prepreg, the silane coupling agent may becontained in the prepreg as a silane coupling agent covered on thefibrous base material for surface treatment in advance.

Examples of the silane coupling agent include a silane coupling agenthaving at least one functional group selected from the group consistingof a vinyl group, a styryl group, a methacryloyl group, an acryloylgroup, and a phenylamino group. In other words, examples of this silanecoupling agent include compounds having at least one of a vinyl group, astyryl group, a methacryloyl group, an acryloyl group, or a phenylaminogroup as a reactive functional group, and further a hydrolyzable groupsuch as a methoxy group or an ethoxy group.

Examples of the silane coupling agent include vinyltriethoxysilane andvinyltrimethoxysilane as those having a vinyl group. Examples of thesilane coupling agent include p-styryltrimethoxysilane andp-styryltriethoxysilane as those having a styryl group. Examples of thesilane coupling agent include 3-methacryloxypropyltrimethoxysilane,3-methacryloxypropylmethyldimethoxysilane,3-methacryloxypropyltriethoxysilane,3-methacryloxypropylmethyldiethoxysilane, and3-methacryloxypropylethyldiethoxysilane as those having a methacryloylgroup. Examples of the silane coupling agent include3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane asthose having an acryloyl group. Examples of the silane coupling agentinclude N-phenyl-3-aminopropyltrimethoxysilane andN-phenyl-3-aminopropyltriethoxysilane as those having a phenylaminogroup.

As described above, the resin composition according to the presentembodiment may contain a flame retardant. The flame retardancy of acured product of the resin composition can be enhanced by containing aflame retardant. The flame retardant is not particularly limited.Specifically, in the field in which halogen-based flame retardants suchas bromine-based flame retardants are used, for example,ethylenedipentabromobenzene, ethylenebistetrabromoimide,decabromodiphenyloxide, and tetradecabromodiphenoxybenzene which have amelting point of 300° C. or more are preferable. It is considered thatthe elimination of halogen at a high temperature and the deteriorationin heat resistance can be suppressed by the use of a halogen-based flameretardant. In the field of being required to be free of halogen, aphosphoric ester-based flame retardant, a phosphazene-based flameretardant, a bis(diphenylphosphine oxide)-based flame retardant, and aphosphinate-based flame retardant are exemplified. Specific examples ofthe phosphoric ester-based flame retardant include a condensedphosphoric ester such as dixylenyl phosphate. Specific examples of thephosphazene-based flame retardant include phenoxyphosphazene. Specificexamples of the bis(diphenylphosphine oxide)-based flame retardantinclude xylylenebis(diphenylphosphine oxide). Specific examples of thephosphinate-based flame retardant include metal phosphinates such asaluminum dialkyl phosphinate. As the flame retardant, the flameretardants exemplified may be used singly or in combination of two ormore kinds thereof.

As described above, the resin composition according to the presentembodiment may contain a filler such as an inorganic filler. Examples ofthe filler include those to be added to enhance the heat resistance andflame retardancy of a cured product of the resin composition, but thefiller is not particularly limited. The heat resistance, flameretardancy and the like can be further enhanced by containing a filler.Specific examples of the filler include silica such as spherical silica,metal oxides such as alumina, titanium oxide, and mica, metal hydroxidessuch as aluminum hydroxide and magnesium hydroxide, tale, aluminumborate, barium sulfate, and calcium carbonate. As the filler, silica,mica, and tale are preferable and spherical silica is more preferableamong these. The filler may be used singly or in combination of two ormore kinds thereof. The filler may be used as it is, or a fillersubjected to a surface treatment with the silane coupling agent may beused. When a filler is contained, the content thereof (filler content)is preferably 30 to 270 mass %, more preferably 50 to 250 mass % withrespect to the resin composition.

(Production Method)

The method for manufacturing the resin composition is not particularlylimited, and examples thereof include a method in which the compound(A), the crosslinking type curing agent (B), and the azo compound (C)are mixed together so as to have predetermined contents. Specificexamples thereof include the method to be described later in the case ofobtaining a varnish-like composition containing an organic solvent.

Moreover, by using the resin composition according to the presentembodiment, a prepreg, a metal-clad laminate, a wiring board, a metalfoil with resin, and a film with resin can be obtained as describedbelow.

[Prepreg]

FIG. 1 is a schematic sectional view illustrating an example of aprepreg 1 according to an embodiment of the present invention.

As illustrated in FIG. 1, the prepreg 1 according to the presentembodiment includes the resin composition or a semi-cured product 2 ofthe resin composition and a fibrous base material 3. This prepreg 1includes the resin composition or the semi-cured product 2 of the resincomposition and the fibrous base material 3 present in the resincomposition or the semi-cured product 2 of the resin composition.

In the present embodiment, the semi-cured product is in a state in whichthe resin composition has been cured to an extent that the resincomposition can be further cured. In other words, the semi-cured productis in a state in which the resin composition has been semi-cured(B-staged). For example, when the resin composition is heated, theviscosity gradually decreases at first, and then curing starts, and theviscosity gradually increases. In such a case, the semi-cured stateincludes a state in which the viscosity has started to increase butcuring is not completed, and the like.

The prepreg to be obtained using the resin composition according to thepresent embodiment may include a semi-cured product of the resincomposition as described above or include the uncured resin compositionitself. In other words, the prepreg may be a prepreg including asemi-cured product of the resin composition (the B-stage resincomposition) and a fibrous base material or a prepreg including theresin composition before being cured (the A-stage resin composition) anda fibrous base material. The resin composition or a semi-cured productof the resin composition may be one obtained by drying or heating anddrying the resin composition.

When manufacturing a prepreg, the resin composition 2 is often preparedin a varnish form and used in order to be impregnated into the fibrousbase material 3 which is a base material for forming the prepreg. Inother words, the resin composition 2 is usually a resin varnish preparedin a varnish form in many cases. Such a varnish-like resin composition(resin varnish) is prepared, for example, as follows.

First, the components which can be dissolved in an organic solvent areintroduced into and dissolved in an organic solvent. At this time,heating may be performed if necessary. Thereafter, components which areused if necessary but are not dissolved in the organic solvent are addedto and dispersed in the solution until a predetermined dispersion stateis achieved using a ball mill, a bead mill, a planetary mixer, a rollmill or the like, whereby a varnish-like resin composition is prepared.The organic solvent to be used here is not particularly limited as longas it dissolves the compound (A), the crosslinking type curing agent(B), the azo compound (C) and the like and does not inhibit the curingreaction. Specific examples thereof include toluene and methyl ethylketone (MEK).

The method for manufacturing the prepreg is not particularly limited aslong as the prepreg can be manufactured. Specifically, whenmanufacturing a prepreg, the resin composition which has been describedabove and is used in the present embodiment is often prepared in avarnish form and used as a resin varnish as described above.

Specific examples of the fibrous base material include glass cloth,aramid cloth, polyester cloth, a glass nonwoven fabric, an aramidnonwoven fabric, a polyester nonwoven fabric, pulp paper, and linterpaper. When glass cloth is used, a laminate exhibiting excellentmechanical strength is obtained, and glass cloth subjected to flatteningis particularly preferable. Specific examples of the flattening includea method in which glass cloth is continuously pressed at an appropriatepressure using a press roll to flatly compress the yarn. The thicknessof the generally used fibrous base material is, for example, 0.01 mm ormore and 0.3 mm or less.

The method for manufacturing the prepreg is not particularly limited aslong as the prepreg can be manufactured. Specifically, whenmanufacturing a prepreg, the resin composition according to the presentembodiment described above is often prepared in a varnish form and usedas a resin varnish as described above.

Examples of the method for manufacturing the prepreg 1 include a methodin which the fibrous base material 3 is impregnated with the resincomposition 2, for example, the resin composition 2 prepared in avarnish form, and then dried.

The fibrous base material 3 is impregnated with the resin composition 2by dipping, coating, and the like. If necessary, the impregnation can berepeated a plurality of times. Moreover, at this time, it is alsopossible to finally adjust the composition and impregnated amount to thedesired composition and impregnated amount by repeating impregnationusing a plurality of resin compositions having different compositionsand concentrations.

The fibrous base material 3 impregnated with the resin composition(resin varnish) 2 is heated under desired heating conditions, forexample, at 80° C. or more and 180° C. or less for 1 minute or more and10 minutes or less. By heating, the prepreg 1 before being cured(A-stage) or in a semi-cured state (B-stage) is obtained. By theheating, the organic solvent can be decreased or removed by beingvolatilized from the resin varnish.

The resin composition according to the present embodiment is a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. Hence, the prepreg including thisresin composition or a semi-cured product of the resin composition is aprepreg which suitably provides a cured product exhibiting lowdielectric properties and high heat resistance. Moreover, this prepregis a prepreg from which a wiring board including an insulating layerexhibiting low dielectric properties and high heat resistance can bemanufactured.

[Metal-Clad Laminate]

FIG. 2 is a schematic sectional view illustrating an example of ametal-clad laminate 11 according to an embodiment of the presentinvention.

As illustrated in FIG. 2, the metal-clad laminate 11 includes aninsulating layer 12 containing a cured product of the prepreg 1illustrated in FIG. 1 and a metal foil 13 to be laminated together withthe insulating layer 12. In other words, the metal-clad laminate 11includes the insulating layer 12 containing a cured product of a resincomposition and the metal foil 13 provided on the insulating layer 12.The insulating layer 12 may be formed of a cured product of the resincomposition or a cured product of the prepreg. The thickness of themetal foil 13 varies depending on the performance and the like to berequired for the finally obtained wiring board and is not particularlylimited. The thickness of the metal foil 13 can be appropriately setdepending on the desired purpose and is preferably, for example, 0.2 to70 μm. Moreover, examples of the metal foil 13 include a copper foil andan aluminum foil, and the metal foil 13 may be a copper foil withcarrier which includes a release layer and a carrier for the improvementin handleability in a case where the metal foil is thin.

The method for manufacturing the metal-clad laminate 11 is notparticularly limited as long as the metal-clad laminate 11 can bemanufactured. Specific examples thereof include a method in which themetal-clad laminate 11 is fabricated using the prepreg 1. Examples ofthis method include a method in which the double-sided metal foil-clador single-sided metal foil-clad laminate 11 is fabricated by stackingone sheet or a plurality of sheets of prepreg 1, further stacking themetal foil 13 such as a copper foil on both or one of upper and lowersurfaces of the prepregs 1, and laminating and integrating the metalfoils 13 and prepregs 1 by heating and pressing. In other words, themetal-clad laminate 11 is obtained by laminating the metal foil 13 onthe prepreg 1 and then performing heating and pressing. The heating andpressing conditions can be appropriately set depending on the thicknessof the metal-clad laminate 11 to be manufactured, the kind of thecomposition of the prepreg 1, and the like. For example, it is possibleto set the temperature to 170° C. to 210° C., the pressure to 3.5 to 4MPa, and the time to 60 to 150 minutes. The metal-clad laminate may bemanufactured without using a prepreg. Examples thereof include a methodin which a varnish-like resin composition is applied on a metal foil toform a layer containing the resin composition on the metal foil and thenheating and pressing is performed.

The resin composition according to the present embodiment is a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. Hence, a metal-clad laminateincluding an insulating layer containing a cured product of this resincomposition is a metal-clad laminate including an insulating layerexhibiting low dielectric properties and high heat resistance. Moreover,this metal-clad laminate is a metal-clad laminate from which a wiringboard including an insulating layer exhibiting low dielectric propertiesand high heat resistance can be manufactured.

[Wiring Board]

FIG. 3 is a schematic sectional view illustrating an example of a wiringboard 21 according to an embodiment of the present invention.

The wiring board 21 according to the present embodiment is formed of aninsulating layer 12 obtained by curing the prepreg 1 illustrated in FIG.1 and wiring 14 which is laminated together with the insulating layer 12and is formed by partially removing the metal foil 13 as illustrated inFIG. 3. In other words, the wiring board 21 includes the insulatinglayer 12 containing a cured product of a resin composition and thewiring 14 provided on the insulating layer 12. The insulating layer 12may be formed of a cured product of the resin composition or a curedproduct of the prepreg.

The method for manufacturing the wiring board 21 is not particularlylimited as long as the wiring board 21 can be manufactured. Specificexamples thereof include a method in which the wiring board 21 isfabricated using the prepreg 1. Examples of this method include a methodin which the wiring board 21, in which wiring is provided as a circuiton the surface of the insulating layer 12, is fabricated by formingwiring through etching and the like of the metal foil 13 on the surfaceof the metal-clad laminate 1 fabricated in the manner described above.In other words, the wiring board 21 is obtained by partially removingthe metal foil 13 on the surface of the metal-clad laminate 11 and thusforming a circuit. Examples of the method for forming a circuit includecircuit formation by a semi-additive process (SAP) or a modifiedsemi-additive process (MSAP) in addition to the method described above.The wiring board 21 includes the insulating layer 12 having a high glasstransition temperature, a low water absorption rate, and sufficientlysuppressed increases in the dielectric constant and dielectric losstangent due to water absorption even after water absorption.

Such a wiring board is a wiring board including an insulating layerexhibiting low dielectric properties and high heat resistance.

[Metal Foil with Resin]

FIG. 4 is a schematic sectional view illustrating an example of a metalfoil with resin 31 according to the present embodiment.

The metal foil with resin 31 according to the present embodimentincludes a resin layer 32 containing the resin composition or asemi-cured product of the resin composition and a metal foil 13 asillustrated in FIG. 4. The metal foil with resin 31 includes the metalfoil 13 on the surface of the resin layer 32. In other words, the metalfoil with resin 31 includes the resin layer 32 and the metal foil 13 tobe laminated together with the resin layer 32. The metal foil with resin31 may include other layers between the resin layer 32 and the metalfoil 13.

The resin layer 32 may contain a semi-cured product of the resincomposition as described above or may contain the uncured resincomposition. In other words, the metal foil with resin 31 may be a metalfoil with resin including a resin layer containing a semi-cured productof the resin composition (the B-stage resin composition) and a metalfoil or a metal foil with resin including a resin layer containing theresin composition before being cured (the A-stage resin composition) anda metal foil. The resin layer is only required to contain the resincomposition or a semi-cured product of the resin composition and may ormay not contain a fibrous base material. The resin composition or asemi-cured product of the resin composition may be one obtained bydrying or heating and drying the resin composition. As the fibrous basematerial, those similar to the fibrous base materials of the prepreg canbe used.

As the metal foil, metal foils to be used in metal-clad laminates can beused without being limited. Examples of the metal foil include a copperfoil and an aluminum foil.

The metal foil with resin 31 and a film with resin 41 may include acover film and the like if necessary. By including a cover film, it ispossible to prevent entry of foreign matter and the like. The cover filmis not particularly limited, and examples thereof include a polyolefinfilm, a polyester film, a polymethylpentene film, and films formed byproviding a release agent layer on these films.

The method for manufacturing the metal foil with resin 31 is notparticularly limited as long as the metal foil with resin 31 can bemanufactured. Examples of the method for manufacturing the metal foilwith resin 31 include a method in which the varnish-like resincomposition (resin varnish) is applied on the metal foil 13 and heatedto manufacture the metal foil with resin 31. The varnish-like resincomposition is applied on the metal foil 13 using, for example, a barcoater. The applied resin composition is heated under the conditions of,for example, 80° C. or more and 180° C. or less and 1 minute or more and10 minutes or less. The heated resin composition is formed as theuncured resin layer 32 on the metal foil 13. By the heating, the organicsolvent can be decreased or removed by being volatilized from the resinvarnish.

The resin composition according to the present embodiment is a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. Hence, the metal foil with resinincluding a resin layer containing this resin composition or asemi-cured product of this resin composition is a metal foil with resinwhich suitably provides a cured product exhibiting low dielectricproperties and high heat resistance. Moreover, this metal foil withresin can be used when manufacturing a wiring board including aninsulating layer exhibiting low dielectric properties and high heatresistance. For example, by laminating the metal foil with resin on awiring board, a multilayer wiring board can be manufactured. As thewiring board obtained by using such a metal foil with resin, a wiringboard including an insulating layer exhibiting low dielectric propertiesand high heat resistance is obtained.

[Film with Resin]

FIG. 5 is a schematic sectional view illustrating an example of a filmwith resin 41 according to the present embodiment.

The film with resin 41 according to the present embodiment includes aresin layer 42 containing the resin composition or a semi-cured productof the resin composition and a support film 43 as illustrated in FIG. 5.The film with resin 41 includes the resin layer 42 and the support film43 to be laminated together with the resin layer 42. The film with resin41 may include other layers between the resin layer 42 and the supportfilm 43.

The resin layer 42 may contain a semi-cured product of the resincomposition as described above or may contain the uncured resincomposition. In other words, the film with resin 41 may be a film withresin including a resin layer containing a semi-cured product of theresin composition (the B-stage resin composition) and a support film ora film with resin including a resin layer containing the resincomposition before being cured (the A-stage resin composition) and asupport film. The resin layer is only required to contain the resincomposition or a semi-cured product of the resin composition and may ormay not contain a fibrous base material. The resin composition or asemi-cured product of the resin composition may be one obtained bydrying or heating and drying the resin composition. As the fibrous basematerial, those similar to the fibrous base materials of the prepreg canbe used.

As the support film 43, support films to be used in films with resin canbe used without being limited. Examples of the support film includeelectrically insulating films such as a polyester film, a polyethyleneterephthalate (PET) film, a polyimide film, a polyparabanic acid film, apolyether ether ketone film, a polyphenylene sulfide film, a polyamidefilm, a polycarbonate film, and a polyarylate film.

The film with resin 41 may include a cover film and the like ifnecessary. By including a cover film, it is possible to prevent entry offoreign matter and the like. The cover film is not particularly limited,and examples thereof include a polyolefin film, a polyester film, and apolymethylpentene film.

The support film and the cover film may be those subjected to surfacetreatments such as a matt treatment, a corona treatment, a releasetreatment, and a roughening treatment if necessary.

The method for manufacturing the film with resin 41 is not particularlylimited as long as the film with resin 41 can be manufactured. Examplesof the method for manufacturing the film with resin 41 include a methodin which the varnish-like resin composition (resin varnish) is appliedon the support film 43 and heated to manufacture the film with resin 41.The varnish-like resin composition is applied on the support film 43using, for example, a bar coater. The applied resin composition isheated under the conditions of, for example, 80° C. or more and 180° C.or less and 1 minute or more and 10 minutes or less. The heated resincomposition is formed as the uncured resin layer 42 on the support film43. By the heating, the organic solvent can be decreased or removed bybeing volatilized from the resin varnish.

The resin composition according to the present embodiment is a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. Hence, the film with resinincluding a resin layer containing this resin composition or asemi-cured product of this resin composition is a film with resin whichsuitably provides a cured product exhibiting low dielectric propertiesand high heat resistance. Moreover, this film with resin can be usedwhen manufacturing a wiring board including an insulating layerexhibiting low dielectric properties and high heat resistance. Amultilayer wiring board can be manufactured, for example, by laminatingthe film with resin on a wiring board and then peeling off the supportfilm from the film with resin or by peeling off the support film fromthe film with resin and then laminating the film with resin on a wiringboard. As the wiring board obtained by using such a film with resin, awiring board including an insulating layer exhibiting low dielectricproperties and high heat resistance is obtained.

The present specification discloses various aspects of a technology asdescribed above, but the main technology is summarized below.

An aspect of the present invention is a resin composition containing acompound (A) having at least one group represented by the followingFormula (1) in a molecule, a crosslinking type curing agent (B), and anazo compound (C) that has an azo group in a molecule and has noheteroatom other than a nitrogen atom constituting the azo group.

In Formula (1), n represents 0 to 10, Z represents an arylene group, andR₁ to R₃ each independently represent a hydrogen atom or an alkyl group.

According to such a configuration, it is possible to provide a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. It is considered that this isbecause a highly polar group such as a CN group is hardly generated inthe cured product of the resin composition when the compound (A) and thecrosslinking type curing agent (B) are reacted using the azo compound(C) as an initiator.

In the resin composition, the azo compound (C) preferably includes anazo initiator represented by the following Formula (2).[Chem. 26]R₄—N═N—R₅  (2)

In Formula (2), R₄ and R₅ each independently represent a hydrogen atomor an alkyl group.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. It is considered that this isbecause the compound (A) and the crosslinking type curing agent (B) canbe suitably reacted while suppressing the generation of highly polargroups such as a CN group in the cured product of the resin compositionwhen the azo compound (C) is used as an initiator.

In the resin composition, the alkyl group of R₄ and R₅ preferably has 1to 8 carbon atoms.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the azo compound (C) preferably includes atleast either of a compound represented by the following Formula (3) or acompound represented by the following Formula (4).

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the weight average molecular weight of thecompound (A) is preferably 1,500 to 40,000.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance and exhibits excellent moldability.

In the resin composition, the equivalent of the vinyl group included inthe group that is represented by Formula (1) and contains a hydrogenatom as R₁ to R₃ in the compound (A) is preferably 250 to 1200.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance and exhibits excellent moldability.

In the resin composition, the compound (A) preferably includes amodified polyphenylene ether compound having the group represented byFormula (1) at the molecule terminal.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the compound (A) preferably includes a polymerhaving a structural unit represented by the following Formula (5) in themolecule.

In Formula (5), Z represents an arylene group, R₁ to R₃ eachindependently represent a hydrogen atom or an alkyl group, and R₆ to R₈each independently represent a hydrogen atom or an alkyl group having 1to 6 carbon atoms.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the compound (A) preferably includes amodified polyphenylene ether compound having the group represented byFormula (1) at the molecule terminal and a polymer having a structuralunit represented by Formula (5) in the molecule.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the content of the modified polyphenyleneether compound is preferably 5 to 50 parts by mass with respect to 100parts by mass of the sum of the modified polyphenylene ether compound,the polymer, and the crosslinking type curing agent (B).

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the content of the polymer is preferably 20 to95 parts by mass with respect to 100 parts by mass of the sum of themodified polyphenylene ether compound, the polymer, and the crosslinkingtype curing agent (B).

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the polymer preferably includes an aromaticpolymer having a structural unit derived from a bifunctional aromaticcompound in which two carbon-carbon unsaturated double bonds are bondedto an aromatic ring as the structural unit represented by Formula (5).In the resin composition, the aromatic polymer may further have astructural unit derived from a monofunctional aromatic compound in whichone carbon-carbon unsaturated double bond is bonded to an aromatic ring.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the structural unit represented by Formula (5)preferably includes a structural unit represented by the followingFormula (6).

In Formula (6), R₆ to R₈ each independently represent a hydrogen atom oran alkyl group having 1 to 6 carbon atoms and R₉ represents an arylenegroup having 6 to 12 carbon atoms.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the structural unit represented by Formula (6)preferably includes a structural unit represented by the followingFormula (7).

In Formula (7), R₆ to R₈ each independently represent a hydrogen atom oran alkyl group having 1 to 6 carbon atoms.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the polymer preferably further has astructural unit represented by the following Formula (8) in themolecule.

In Formula (8), R₁₀ to R₁₂ each independently represent a hydrogen atomor an alkyl group having 1 to 6 carbon atoms and R₁₃ represents an arylgroup.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the aryl group in the structural unitrepresented by Formula (8) preferably includes an aryl group having analkyl group having 1 to 6 carbon atoms.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the crosslinking type curing agent (B)preferably includes at least one selected from the group consisting ofstyrene, divinylbenzene, a trialkenyl isocyanurate compound, apolybutadiene compound, a maleimide compound, and an acenaphthylenecompound.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the maleimide compound preferably includes amonofunctional maleimide compound having one maleimide group in themolecule.

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

In the resin composition, the monofunctional maleimide compoundpreferably includes a compound represented by the following Formula (9)or a compound represented by the following Formula (10).

According to such a configuration, it is possible to obtain a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance.

Another aspect of the present invention is a prepreg including the resincomposition or a semi-cured product of the resin composition, and afibrous base material.

According to such a configuration, it is possible to provide a prepregwhich suitably provides a cured product exhibiting low dielectricproperties and high heat resistance.

Another aspect of the present invention is a film with resin including aresin layer containing the resin composition or a semi-cured product ofthe resin composition, and a support film.

According to such a configuration, it is possible to provide a film withresin which suitably provides a cured product exhibiting low dielectricproperties and high heat resistance.

Another aspect of the present invention is a metal foil with resinincluding a resin layer containing the resin composition or a semi-curedproduct of the resin composition, and a metal foil.

According to such a configuration, it is possible to provide a metalfoil with resin which suitably provides a cured product exhibiting lowdielectric properties and high heat resistance.

Another aspect of the present invention is a metal-clad laminateincluding an insulating layer containing a cured product of the resincomposition or a cured product of the prepreg, and a metal foil.

According to such a configuration, it is possible to provide ametal-clad laminate which includes an insulating layer exhibiting lowdielectric properties and high heat resistance.

Another aspect of the present invention is a wiring board including aninsulating layer containing a cured product of the resin composition ora cured product of the prepreg, and wiring.

According to such a configuration, it is possible to provide a wiringboard which includes an insulating layer exhibiting low dielectricproperties and high heat resistance.

According to the present invention, it is possible to provide a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. According to the present invention,it is possible to provide a prepreg, a film with resin, a metal foilwith resin, a metal-clad laminate, and a wiring board which are obtainedusing the resin composition.

Hereinafter, the present invention will be described more specificallywith reference to Examples, but the scope of the present invention isnot limited thereto.

EXAMPLES Examples 1 to 17 and Comparative Examples 1 to 10

The respective components to be used when preparing resin compositionsin the present Examples will be described.

(Resin Compound)

Modified PPE1: Modified polyphenylene ether compound having a grouprepresented by Formula (1) at the molecular terminal, specifically, amodified polyphenylene ether compound obtained by reacting polyphenyleneether with chloromethylstyrene. Namely, the compound (A) having at leastone group represented by Formula (1) in the molecule.

More specifically, a modified polyphenylene ether compound obtained byperforming a reaction as follows.

First, 200 g of polyphenylene ether (SA90 manufactured by SABICInnovative Plastics IP BV, number of terminal hydroxyl groups: 2, weightaverage molecular weight Mw: 1700), 30 g of a mixture containingp-chloromethylstyrene and m-chloromethylstyrene at a mass ratio of 50:50(chloromethylstyrene: CMS manufactured by Tokyo Chemical Industry Co.,Ltd.), 1.227 g of tetra-n-butylammonium bromide as a phase transfercatalyst, and 400 g of toluene were introduced into a 1-literthree-necked flask equipped with a temperature controller, a stirrer,cooling equipment, and a dropping funnel and stirred. Moreover, themixture was stirred until polyphenylene ether, chloromethylstyrene, andtetra-n-butylammonium bromide were dissolved in toluene. At that time,the mixture was gradually heated until the liquid temperature finallyreached 75° C. Thereafter, an aqueous sodium hydroxide solution (20 g ofsodium hydroxide/20 g of water) as an alkali metal hydroxide was addeddropwise to the solution over 20 minutes. Thereafter, the mixture wasfurther stirred at 75° C. for 4 hours. Next, the resultant in the flaskwas neutralized with hydrochloric acid at 10% by mass and then a largeamount of methanol was added into the flask. By doing so, a precipitatewas generated in the liquid in the flask. In other words, the productcontained in the reaction solution in the flask was reprecipitated.Thereafter, this precipitate was taken out by filtration, washed threetimes with a mixed solution of methanol and water contained at a massratio of 80:20, and then dried under reduced pressure at 80° C. for 3hours.

The obtained solid was analyzed by ¹H-NMR (400 MHz, CDCl₃, TMS). As aresult of NMR measurement, a peak attributed to a vinylbenzyl group(ethenylbenzyl group) was observed at 5 to 7 ppm. This made it possibleto confirm that the obtained solid was a modified polyphenylene ethercompound having a vinylbenzyl group (ethenylbenzyl group) as thesubstituent at the molecular terminal in the molecule. Specifically, itwas confirmed that the solid obtained was ethenylbenzylatedpolyphenylene ether. This obtained modified polyphenylene ether compoundwas a modified polyphenylene ether compound represented by Formula (19),where Y was a dimethylmethylene group (a group represented by Formula(17), where R₄₂ and R₄₃ were a methyl group), Z was a phenylene group,R₁ to R₃ were a hydrogen atom, and n was 1.

The number of terminal functional groups in the modified polyphenyleneether compound was measured as follows.

First, the modified polyphenylene ether compound was accurately weighed.The weight at that time is defined as X (mg). Thereafter, this modifiedpolyphenylene ether compound weighed was dissolved in 25 mL of methylenechloride, 100 μL of an ethanol solution of tetraethylammonium hydroxide(TEAH) at 10 mass % (TEAH:ethanol (volume ratio)=15:85) was added to thesolution, and then the absorbance (Abs) of this mixture at 318 nm wasmeasured using a UV spectrophotometer (UV-1600 manufactured by ShimadzuCorporation). Thereafter, the number of terminal hydroxyl groups in themodified polyphenylene ether compound was calculated from themeasurement result using the following equation.Residual OH amount (μmol/g)=[(25×Abs)/(ε×OPL×X)]×10⁶

Here, ε indicates the extinction coefficient and is 4700 L/mol·cm. OPLindicates the cell path length and is 1 cm.

Since the calculated residual OH amount (the number of terminal hydroxylgroups) in the modified polyphenylene ether compound is almost zero, ithas been found that the hydroxyl groups in the polyphenylene etherbefore being modified have almost been modified. From this fact, it hasbeen found that the number of terminal hydroxyl groups decreased fromthe number of terminal hydroxyl groups in polyphenylene ether beforebeing modified is the number of terminal hydroxyl groups inpolyphenylene ether before being modified. In other words, it has beenfound that the number of terminal hydroxyl groups in polyphenylene etherbefore being modified is the number of terminal functional groups in themodified polyphenylene ether compound. That is, the number of terminalfunctional groups was two.

The intrinsic viscosity (IV) of the modified polyphenylene ethercompound was measured in methylene chloride at 25° C. Specifically, theintrinsic viscosity (IV) of the modified polyphenylene ether compoundwas measured in a methylene chloride solution (liquid temperature: 25°C.) of the modified polyphenylene ether compound at 0.18 g/45 ml using aviscometer (AVS500 Visco System manufactured by SCHOTT InstrumentsGmbH). As a result, the intrinsic viscosity (IV) of the modifiedpolyphenylene ether compound was 0.086 dl/g.

The molecular weight distribution of the modified polyphenylene ethercompound was measured by GPC. Moreover, the weight average molecularweight (Mw) was calculated from the obtained molecular weightdistribution. As a result, Mw was 2,300.

The equivalent (vinyl equivalent) of the vinyl group included in thegroup that was represented by Formula (1) and contained a hydrogen atomas R₁ to R₃ in the modified polyphenylene ether compound was calculatedthrough iodine value measurement by the Wyeth method. Specifically, thecompound to be measured was first dissolved in chloroform so that theconcentration was 0.3 g/35 mL to 0.3 g/25 mL Excess amount of iodinechloride was added to the double bonds present in this solution. Bydoing so, the double bond was reacted with iodine chloride, thisreaction proceeded sufficiently, and then a 20 mass % potassium iodideaqueous solution was added to the solution after being subjected to thereaction to extract the iodine component remaining in the solution afterbeing subjected to the reaction into the aqueous phase in the form of I₃⁻. This aqueous phase into which I₃ ⁻ was extracted was titrated with asodium thiosulfate aqueous solution (0.1 mol/L sodium thiosulfatestandard solution), and the iodine value was calculated. The followingequation was used to calculate the iodine value.Iodine value=[(B−A)×F×1.269]/mass of compound (g)In the equation, B denotes the titration volume (cc) of the 0.1 mol/Lsodium thiosulfate standard solution required for the blank test, Adenotes the titration volume (cc) of 0.1 mol/L sodium thiosulfatestandard solution required for neutralization, and F denotes the titerof sodium thiosulfate.

As a result of the measurement, the equivalent (vinyl equivalent) of thevinyl group included in the group that was represented by Formula (1)and contained a hydrogen atom as R₁ to R₃ in the modified polyphenyleneether compound was 1000.

Modified PPE2: Modified polyphenylene ether compound having avinylbenzyl group (ethenylbenzyl group) at the terminal (OPE-2st 1200manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC., the compound (A)having at least one group represented by Formula (1) in the molecule,Mw: 1400, and a modified polyphenylene ether compound represented byFormula (18), where Z is a phenylene group, R₁ to R₃ are a hydrogenatom, and n is 0)

Polymer 1: ODV-XET (X03) manufactured by NIPPON STEEL Chemical &Materials Co., Ltd. (a polymer having a structural unit represented byFormula (5) in the molecule: an aromatic polymer having a structuralunit derived from a bifunctional aromatic compound in which twocarbon-carbon unsaturated double bonds are bonded to an aromatic ringand at least one group represented by Formula (1), a compound havingstructural units represented by Formulas (20) to (22) (the compound (A)having at least one group represented by Formula (1) in the molecule),weight average molecular weight Mw: 26300, equivalent (vinyl equivalent)of the vinyl group included in the group that was represented by Formula(1) and contained a hydrogen atom as R₁ to R₃: 510)

Polymer 2: ODV-XET (X04) manufactured by NIPPON STEEL Chemical &Materials Co., Ltd. (a polymer having a structural unit represented byFormula (5) in the molecule: an aromatic polymer having a structuralunit derived from a bifunctional aromatic compound in which twocarbon-carbon unsaturated double bonds are bonded to an aromatic ringand at least one group represented by Formula (1), a compound havingstructural units represented by Formulas (20) to (22) (the compound (A)having at least one group represented by Formula (1) in the molecule),weight average molecular weight Mw: 31100, equivalent (vinyl equivalent)of the vinyl group included in the group that was represented by Formula(1) and contained a hydrogen atom as R₁ to R₃: 380)

Polymer 3: ODV-XET (X05) manufactured by NIPPON STEEL Chemical &Materials Co., Ltd. (a polymer having a structural unit represented byFormula (5) in the molecule: an aromatic polymer having a structuralunit derived from a bifunctional aromatic compound in which twocarbon-carbon unsaturated double bonds are bonded to an aromatic ringand at least one group represented by Formula (1), a compound havingstructural units represented by Formulas (20) to (22) (the compound (A)having at least one group represented by Formula (1) in the molecule),weight average molecular weight Mw: 39500, equivalent (vinyl equivalent)of the vinyl group included in the group that was represented by Formula(1) and contained a hydrogen atom as R₁ to R₃: 320)

The equivalent (vinyl equivalent) of the vinyl group included in thegroup that was represented by Formula (1) and contained a hydrogen atomas R₁ to R₃ in the polymers 1 to 3 was calculated through iodine valuemeasurement by the Wyeth method. Specifically, the compound to bemeasured was first dissolved in chloroform so that the concentration was0.3 g/35 mL to 0.3 g/25 mL. Excess amount of iodine chloride was addedto the double bonds present in this solution. By doing so, the doublebond was reacted with iodine chloride, this reaction proceededsufficiently, and then a 20 mass % potassium iodide aqueous solution wasadded to the solution after being subjected to the reaction to extractthe iodine component remaining in the solution after being subjected tothe reaction into the aqueous phase in the form of I₃ ⁻. This aqueousphase into which I₃ ⁻ was extracted was titrated with a sodiumthiosulfate aqueous solution (0.1 mol/L sodium thiosulfate standardsolution), and the iodine value was calculated. The following equationwas used to calculate the iodine value.Iodine value=[(B−A)×F×1.269]/mass of compound (g)

In the equation, B denotes the titration volume (cc) of the 0.1 mol/Lsodium thiosulfate standard solution required for the blank test, Adenotes the titration volume (cc) of 0.1 mol/L sodium thiosulfatestandard solution required for neutralization, and F denotes the titerof sodium thiosulfate.

Butadiene-styrene oligomer: Ricon 100 manufactured by CRAY VALLEY

(Crosslinking Type Curing Agent)

Triallyl isocyanurate: TAIC manufactured by Nihon Kasei CO., LTD.

Divinylbenzene: DVB810 manufactured by NIPPON STEEL Chemical & MaterialsCo., Ltd.

Polybutadiene: B-1000 manufactured by NIPPON SODA CO., LTD.

Bifunctional maleimide:3,3-Dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide (BMI-5100manufactured by Daiwa Kasei Industry Co., Ltd.)

Monofunctional maleimide 1: IMILEX C manufactured by NIPPON SHOKUBAICO., LTD. (compound represented by Formula (9))

Monofunctional maleimide 2: IMILEX P manufactured by NIPPON SHOKUBAICO., LTD. (compound represented by formula (10))

Acenaphthylene: Acenaphthylene manufactured by JFE Chemical Corporation

Methacryl-modified PPE: Modified polyphenylene ether obtained bymodifying the terminal hydroxyl groups of polyphenylene ether with amethacryl group (a methacryl-modified polyphenylene ether compoundrepresented by Formula (23), where Y is a dimethylmethylene group (agroup represented by Formula (17), where R₄₂ and R₄₃ are a methylgroup), SA9000 manufactured by SABIC Innovative Plastics, weight averagemolecular weight Mw: 2000, number of terminal functional groups: 2)

(Initiator)

Azo initiator 1: VR-110 manufactured by FUJIFILM Wako Pure ChemicalCorporation (an azo compound which has an azo group in the molecule andhas no hetero atom other than the nitrogen atom constituting the azogroup, a compound represented by Formula (3))

Azo initiator 2: VAm-110 manufactured by FUJIFILM Wako Pure ChemicalCorporation (an azo compound which has an azo group in the molecule andhas no hetero atom other than the nitrogen atom constituting the azogroup, 2,2′-azobis(N-butyl-2-methylpropionamide))

Peroxide: α,α′-di(t-butylperoxy)diisopropylbenzene (Perbutyl P (PBP)manufactured by NOF CORPORATION)

(Preparation Method)

First, the respective components were added to and mixed in toluene atthe composition (parts by mass) presented in Tables 3 to 5 so that thesolid concentration was 55% by mass. The mixture was stirred for 60minutes. By doing so, a varnish-like resin composition (varnish) wasobtained.

Next, the obtained varnish was impregnated into a fibrous base material(glass cloth: L2116, #2116 type, L Glass manufactured by Asahi KaseiCorporation) and then heated and dried at 110° C. for about 2 to 8minutes, thereby fabricating a prepreg. At that time, the content (resincontent) of the components constituting the resin by the curingreaction, such as a resin compound, a crosslinking type curing agent,and an initiator, with respect to the prepreg was adjusted to be about55% by mass.

Thereafter, each of the obtained prepregs was stacked by six sheets andheated to a temperature of 200° C. at a rate of temperature rise of 3.5°C./min and heated and pressed under the conditions of 200° C., 120minutes, and a pressure of 3 MPa, thereby obtaining an evaluationsubstrate (cured product of prepreg).

The varnish, prepreg, and evaluation substrate prepared in the mannerdescribed above were evaluated by the following methods.

[Dielectric Loss Tangent]

The dielectric loss tangent of the evaluation substrate at 10 GHz wasmeasured by the cavity resonator perturbation method. Specifically, thedielectric loss tangent of the evaluation substrate at 10 GHz wasmeasured using a network analyzer (N5230A manufactured by KeysightTechnologies).

[Oven Heat Resistance]

In conformity to the JIS C 6481 standard, the evaluation substrate wasleft to stand for 1 hour in a thermostat set to a predeterminedtemperature and then taken out. Thereafter, the taken out metal-cladlaminate was visually observed. If abnormality such as swelling was notconfirmed even when the temperature was 280° C., the oven heatresistance was evaluated as “Very Good”. If abnormality such as swellingwas confirmed when the temperature was 280° C. but abnormality such asswelling was not confirmed when the temperature was 260° C., the ovenheat resistance was evaluated as “Good”. If abnormality such as swellingwas confirmed when the temperature was 260° C., the oven heat resistancewas evaluated as “Poor”.

[Solder Heat Resistance]

A copper foil-clad laminate (metal foil-clad laminate) having athickness of about 0.8 mm and copper foils attached to both sidesthereof was obtained by setting the number of prepregs to be stacked tosix sheets when fabricating the evaluation substrate. This formed copperfoil-clad laminate was cut into 50 mm×50 mm and the copper foils on bothsides were removed by etching. The laminate for evaluation thus obtainedwas held for 6 hours under at a temperature of 121° C. and a relativehumidity of 100%. Thereafter, this laminate for evaluation was immersedin a solder bath at 288° C. for 10 seconds. The immersed laminate wasvisually observed to confirm the occurrence of measling and swelling. Ifthe occurrence of measling and swelling was not confirmed, the solderheat resistance was evaluated as “Very Good”. Separately, similarevaluation was performed using a solder bath at 260° C. instead of thesolder bath at 288° C. If the occurrence of measling and swelling wasconfirmed at 288° C. but the occurrence of measling and swelling was notconfirmed at 260° C., the solder heat resistance was evaluated as“Good”. If the occurrence of measling and swelling was confirmed even at260° C., the solder heat resistance was evaluated as “Poor”.

The results of the respective evaluations are presented in Tables 3 to5.

TABLE 3 Examples 1 2 3 4 5 6 Composition Resin Modified PPE1 70 70 70 7070 70 (parts by compound Modified PPE2 — — — — — — mass)Butadiene-styrene — — — — — — oligomer Crosslinking Triallyl 30 30 30 —— — type curing isocyanurate agent Divinylbenzene — — — 30 — —Polybutadiene — — — — 30 — Bifunctional — — — — — 30 maleimideMonofunctional — — — — — — maleimide 1 Monofunctional — — — — — —maleimide 2 Acenaphthylene — — — — — — Initiator Azo initiator 1  1 0.5  2  1  1  1 Azo initiator 2 — — — — — — Peroxide — — — — — — EvaluationDielectric loss tangent     0.0022     0.0022     0.0022     0.0021    0.0021     0.0023 Heat Oven heat Very Very Good Very Good Veryresistance resistance Good Good Good Good Moisture Very Very Good GoodVery Very absorption Good Good Good Good solder heat resistance ExamplesComparative Example 7 8 9 10 1 Composition Resin Modified PPE1 70 70 70— 70 (parts by compound Modified PPE2 — — — 70 — mass) Butadiene-styrene— — — — — oligomer Crosslinking Triallyl — — — 30 — type curingisocyanurate agent Divinylbenzene — — — — — Polybutadiene — — — — —Bifunctional — — — — — maleimide Monofunctional 30 — — — 30 maleimide 1Monofunctional — 30 — — — maleimide 2 Acenaphthylene — — 30 — —Initiator Azo initiator 1  1  1  1  1 — Azo initiator 2 — — — —  1Peroxide — — — — — Evaluation Dielectric loss tangent     0.0021    0.0022     0.0021     0.0022     0.0028 Heat Oven heat Very VeryVery Very Good resistance resistance Good Good Good Good Moisture VeryVery Very Very Good absorption Good Good Good Good solder heatresistance Comparative Example 2 3 4 5 6 Composition Resin Modified PPE170 — 70 — — (parts by compound Modified PPE2 — — — 70 70 mass)Butadiene-styrene — 70 — — — oligomer Crosslinking Triallyl isocyanurate— 30 30 — — type curing Divinylbenzene — — — — — agent Polybutadiene — —— — — Bifunctional maleimide — — — — — Monofunctional 30 — — 30 30maleimide 1 Monofunctional — — — — — maleimide 2 Acenaphthylene — — — —— Initiator Azo initiator 1 —  1 — — — Azo initiator 2 — — — 1 —Peroxide  1 — —  —  1 Evaluation Dielectric loss tangent     0.0029    0.0020     0.0022     0.0028     0.0029 Heat Oven heat Very PoorPoor Good Very resistance resistance Good Good Moisture Very Poor PoorGood Very absorption Good Good solder heat resistance

TABLE 4 Examples 11 12 13 14 15 Composition Resin Modified PPE1 — — — —— (parts by compound Polymer 1 — — 70 — — mass) Polymer 2 70 70 — 70 —Polymer 3 — — — — 70 Butadiene-styrene oligomer — — — — — CrosslinkingTriallyl isocyanurate 30 — — — — type curing Divinylbenzene — — 30 30 30agent Acenaphthylene — 30 — — — Methacryl-modified PPE — — — — —Initiator Azo initiator 1 1 1 1 1 1 Azo initiator 2 — — — — — Peroxide —— — — — Evaluation Dielectric loss tangent 0.0019 0.0018 0.0018 0.00180.0018 Heat Oven heat Good Very Very Very Very resistance resistanceGood Good Good Good Moisture Good Very Very Very Very absorption GoodGood Good Good solder heat resistance Examples Comparative Example 16 173 4 7 Composition Resin Modified PPE1 30 — — 70 — (parts by compoundPolymer 1 — — — — — mass) Polymer 2 40 70 — — 70 Polymer 3 — — — — —Butadiene-styrene oligomer — — 70 — — Crosslinking Triallyl isocyanurate— — 30 30 — type curing Divinylbenzene — 20 — — 30 agent Acenaphthylene30 — — — — Methacryl-modified PPE — 10 — — — Initiator Azo initiator 1 11 1 — — Azo initiator 2 — — — — 1 Peroxide — — — — — EvaluationDielectric loss tangent 0.0021 0.0021 0.0020 0.0022 0.0024 Heat Ovenheat Very Very Poor Poor Good resistance resistance Good Good MoistureVery Very Poor Poor Good absorption Good Good solder heat resistanceComparative Example 8 9 10 Composition Resin Modified PPE1 — 70 70(parts by compound Polymer 1 — — — mass) Polymer 2 70 — — Polymer 3 — —— Butadiene-styrene oligomer — — — Crosslinking Triallyl isocyanurate —— — type curing Divinylbenzene 30 30 30 agent Acenaphthylene — — —Methacryl-modified PPE — — — Initiator Azo initiator 1 — — — Azoinitiator 2 — 1 — Peroxide 1 — 1 Evaluation Dielectric loss tangent0.0024 0.0028 0.0028 Heat Oven heat Very Good Very resistance resistanceGood Good Moisture Very Good Very absorption Good Good solder heatresistance

As can be seen from Tables 3 and 4, when resin compositions containingthe compound (A) having at least one group represented by Formula (1) inthe molecule and the crosslinking type curing agent (B) contains the azocompound (C) (azo compound 1) that has an azo group in the molecule andhas no heteroatom other than the nitrogen atom constituting the azogroup (Examples 1 to 17), the dielectric loss tangent is low and theoven heat resistance and the moisture absorption solder heat resistanceare also high. From this fact, it can be seen that these resincompositions are resin compositions which provide cured productsexhibiting low dielectric properties and high heat resistance. It isconsidered that this is because the azo compound 1 is used as aninitiator for reacting the compound (A) with the crosslinking typecuring agent (B). More specifically, it is considered that this isbecause a highly polar group such as a CN group is hardly generated inthe cured product of the resin composition when the compound (A) and thecrosslinking type curing agent (B) are reacted using the azo compound 1as an initiator.

In contrast, in the case of containing not the azo compound 1 but an azocompound (azo compound 2) containing a hetero atom in addition to thenitrogen atom constituting the azo group (Comparative Example 1,Comparative Example 5, Comparative Example 7, and Comparative Example9), the dielectric loss tangent is higher than that in Examples 1 to 17.It is considered that this is because this azo compound 2 also acts asan initiator similarly to the azo compound 1, and a cured productexhibiting high heat resistance is thus obtained, but a highly polargroup such as a CN group is easily generated in the cured product of theresin composition.

Even in the case of containing not the azo compound 1 but a peroxide(Comparative Example 2, Comparative Example 6, Comparative Example 8,and Comparative Example 10), the dielectric loss tangent is higher thanthat in Examples 1 to 17. It is considered that this is because theperoxide acts as an initiator and a cured product exhibiting high heatresistance is thus obtained, but a highly polar group such as a hydroxylgroup is easily generated in the cured product of the resin composition.

In the case of containing not the compound (A) but a compound which doesnot have a group represented by Formula (1) in the molecule (ComparativeExample 3), the curability is considered to decrease, and a curedproduct exhibiting sufficiently high heat resistance is not obtained.

In the case of not containing a compound which can act as an initiatorsuch as the azo compound 1 (Comparative Example 4) as well, thecurability is considered to decrease, and a cured product exhibitingsufficiently high heat resistance is not obtained.

The resin flowability and circuit filling property of the prepregprepared in the manner described above were evaluated by the followingmethods.

[Resin Flowability of Prepreg]

The resin flowability of each prepreg was measured by a methodconforming to JIS C 6521.

[Circuit Filling Property of Prepreg]

A copper foil having a thickness of 35 μm (GTHMP35 manufactured byFurukawa Electric Co., Ltd.) was laminated on both sides of the prepreg,and this laminated body as a body to be pressed was heated and pressedfor 90 minutes at a temperature of 220° C. and a pressure of 30 kg/cm²to obtain a copper foil-clad laminate (metal foil-clad laminate) havinga thickness of about 0.1 mm and copper foils attached on both sidesthereof. A grid-like pattern was formed on the copper foils on bothsides of this copper foil-clad laminate so that the remaining copperrate on each side was 50%, and wiring was thus formed. The prepregs werelaminated on both sides of the substrate on which this wiring was formedone on each side, a copper foil having a thickness of 12 μm (GTHMP12manufactured by Furukawa Electric Co., Ltd.) was further laminatedthereon, and heating and pressurization were performed using thislaminate as a body to be pressed under the same conditions as when thecopper foil-clad laminate was manufactured. The double-sided copper foilof this formed laminate was removed by etching. In the laminate forevaluation thus obtained, if the resin composition derived from theprepreg sufficiently entered between the circuits and the formation ofvoids was not confirmed, the circuit filling property was evaluated as“Good”. If the resin composition derived from the prepreg insufficientlyentered between the circuits and the formation of voids was confirmed,the circuit filling property was evaluated as “Poor”. Incidentally, thevoids can be visually confirmed.

The results of the respective evaluations are presented in Table 5.

TABLE 5 Examples Comparative Example 4 14 7 8 9 10 Composition ResinModified PPE1 70 — — — 70 70 (parts by compound Polymer 2 — 70 70 70 — —mass) Crosslinking Divinylbenzene 30 30 30 30 30 30 type curing agentInitiator Azo initiator 1  1  1 — — — — Azo initiator 2 — —  1 —  1 —Peroxide — — —  1 —  1 Prepreg Resin flowability 10 10 10  3 10  4Evaluation Circuit filling property Good Good Good Poor Good PoorLaminate Dielectric loss tangent     0.0021     0.0018     0.0024    0.0024     0.0028     0.0028 Evaluation Heat Oven heat Very VeryGood Very Good Very resistance resistance Good Good Good Good MoistureVery Very Good Very Good Very absorption Good Good Good Good solder heatresistance

As can be seen from Table 5, when resin compositions containing thecompound (A) having at least one group represented by Formula (1) in themolecule and the crosslinking type curing agent (B) contains the azocompound (C) (azo compound 1) that has an azo group in the molecule andhas no heteroatom other than the nitrogen atom constituting the azogroup (Example 4 and Example 14), it can be seen that the resinflowability is higher and the circuit filling property is superior toresin compositions which do not contain the azo compound 1 but contain aperoxide (Comparative Example 8 and Comparative Example 10).

This application is based on Japanese Patent Application No. 2018-087155filed on Apr. 27, 2018, Japanese Patent Application No. 2018-136061filed on Jul. 19, 2018, and Japanese Patent Application No. 2019-045680filed on Mar. 13, 2019, the contents of which are incorporated herein.

In order to express the present invention, the present invention hasbeen described above appropriately and sufficiently through theembodiments. However, it should be recognized by those skilled in theart that changes and/or improvements of the above-described embodimentscan be readily made. Accordingly, changes or improvements made by thoseskilled in the art shall be construed as being included in the scope ofthe claims unless otherwise the changes or improvements are at the levelwhich departs from the scope of the appended claims.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to provide a resincomposition which provides a cured product exhibiting low dielectricproperties and high heat resistance. In addition, according to thepresent invention, a prepreg, a film with resin, a metal foil withresin, a metal-clad laminate, and a wiring board which are obtainedusing the resin composition are provided.

The invention claimed is:
 1. A resin composition comprising: a compound(A) having at least one group represented by the following Formula (1)in a molecule; a crosslinking type curing agent (B); and an azo compound(C) that has an azo group in a molecule and has no heteroatom other thana nitrogen atom constituting the azo group:

(in Formula (1), n represents 0 to 10, Z represents an arylene group,and R₁ to R₃ each independently represent a hydrogen atom or an alkylgroup).
 2. The resin composition according to claim 1, wherein the azocompound (C) includes a compound represented by the following Formula(2):[Chem. 2]R₄—N═N—R₅  (2) (in Formula (2), R₄ and R₅ each independently represent ahydrogen atom or an alkyl group).
 3. The resin composition according toclaim 2, wherein the alkyl group of R₄ and R₅ has 1 to 8 carbon atoms.4. The resin composition according to claim 1, wherein the azo compound(C) includes at least either of a compound represented by the followingFormula (3) or a compound represented by the following Formula (4),


5. The resin composition according to claim 1, wherein the compound (A)has a weight average molecular weight of 1500 to 40,000.
 6. The resincomposition according to claim 1, wherein an equivalent of a vinyl groupincluded in the group that is represented by the Formula (1) andcontains a hydrogen atom as R₁ to R₃ in the compound (A) is 250 to 1200.7. The resin composition according to claim 1, wherein the compound (A)includes a modified polyphenylene ether compound having the grouprepresented by the Formula (1) at a molecule terminal.
 8. The resincomposition according to claim 1, wherein the compound (A) includes apolymer having a structural unit represented by the following Formula(5) in a molecule:

(in Formula (5), Z represents an arylene group, R₁ to R₃ eachindependently represent a hydrogen atom or an alkyl group, and R₆ to R₈each independently represent a hydrogen atom or an alkyl group having 1to 6 carbon atoms).
 9. The resin composition according to claim 1,wherein the compound (A) includes a modified polyphenylene ethercompound having the group represented by the Formula (1) at a moleculeterminal and a polymer having a structural unit represented by thefollowing Formula (5) in a molecule:

(in Formula (5), Z represents an arylene group, R₁ to R₃ eachindependently represent a hydrogen atom or an alkyl group, and R₆ to R₈each independently represent a hydrogen atom or an alkyl group having 1to 6 carbon atoms).
 10. The resin composition according to claim 9,wherein a content of the modified polyphenylene ether compound is 5 to50 parts by mass with respect to 100 parts by mass of a sum of themodified polyphenylene ether compound, the polymer, and the crosslinkingtype curing agent (B).
 11. The resin composition according to claim 9,wherein a content of the polymer is 20 to 95 parts by mass with respectto 100 parts by mass of a sum of the modified polyphenylene ethercompound, the polymer, and the crosslinking type curing agent (B). 12.The resin composition according to claim 8, wherein the polymer includesan aromatic polymer having a structural unit derived from a bifunctionalaromatic compound in which two carbon-carbon unsaturated double bondsare bonded to an aromatic ring as the structural unit represented by theFormula (5).
 13. The resin composition according to claim 12, whereinthe aromatic polymer further has a structural unit derived from amonofunctional aromatic compound in which one carbon-carbon unsaturateddouble bond is bonded to an aromatic ring.
 14. The resin compositionaccording to claim 8, wherein the structural unit represented by theFormula (5) includes a structural unit represented by the followingFormula (6):

(in Formula (6), R₆ to R₈ each independently represent a hydrogen atomor an alkyl group having 1 to 6 carbon atoms and R₉ represents anarylene group having 6 to 12 carbon atoms).
 15. The resin compositionaccording to claim 14, wherein the structural unit represented by theFormula (6) includes a structural unit represented by the followingFormula (7):

(in Formula (7), R₆ to R₈ each independently represent a hydrogen atomor an alkyl group having 1 to 6 carbon atoms).
 16. The resin compositionaccording to claim 8, wherein the polymer further has a structural unitrepresented by the following Formula (8) in a molecule:

(in Formula (8), R₁₀ to R₁₂ each independently represent a hydrogen atomor an alkyl group having 1 to 6 carbon atoms and R₁₃ represents an arylgroup).
 17. The resin composition according to claim 16, wherein thearyl group in the structural unit represented by the Formula (8)includes an aryl group having an alkyl group having 1 to 6 carbon atoms.18. The resin composition according to claim 1, wherein the crosslinkingtype curing agent (B) includes at least one selected from a groupconsisting of styrene, divinylbenzene, a trialkenyl isocyanuratecompound, a polybutadiene compound, a maleimide compound, and anacenaphthylene compound.
 19. A prepreg comprising: the resin compositionaccording to claim 1 or a semi-cured product of the resin composition;and a fibrous base material.
 20. A film with resin comprising: a resinlayer containing the resin composition according to claim 1 or asemi-cured product of the resin composition; and a support film.
 21. Ametal foil with resin comprising: a resin layer containing the resincomposition according to claim 1 or a semi-cured product of the resincomposition; and a metal foil.
 22. A metal-clad laminate comprising: aninsulating layer containing a cured product of the resin compositionaccording to claim 1; and a metal foil.
 23. A wiring board comprising:an insulating layer containing a cured product of the resin compositionaccording to claim 1; and wiring.
 24. A metal-clad laminate comprising:an insulating layer containing a cured product of the prepreg accordingto claim 19; and a metal foil.
 25. A wiring board comprising: aninsulating layer containing a cured product of the prepreg according toclaim 19; and wiring.